Maharashtra Board Class 6 Science Chapter 12 Simple Machines Solutions

Simple Machines Class 6 Science Chapter 12 Questions And Answers Maharashtra Board

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 12 Simple Machines Notes, Textbook Exercise Important Questions and Answers.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र कक्षा 6 के विज्ञान के अध्याय 12, 'सरल मशीनें' के शीर्षक को दर्शाता है, जिसमें एक शिक्षिका सरल मशीनों के विषय पर संकेत कर रही है। यह अध्याय सरल मशीनों से संबंधित प्रश्नों और उत्तरों पर केंद्रित है।

Std 6 Science Chapter 12 Simple Machines Question Answer Maharashtra Board

Class 6 Science Chapter 12 Simple Machines Question Answer Maharashtra Board

 

Question 1. Classify the following as a lever, a pulley and an inclined plane: (A wedge, a needle, a staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener, an axe, a crane, a knife)
Answer:

Inclined plane	Pulley	Lever
Wedge	Wheel of flagpole	Nutcracker
Needle	Crane	Scissors
Staircase		Opener
Slide
Axe
Knife.

In simple words: Machines like wedges and slides use a sloped surface (inclined plane), while flagpoles and cranes use wheels and ropes (pulleys), and nutcrackers and scissors apply force around a pivot (levers).

🎯 Exam Tip: Focus on identifying the primary function and structural characteristic of each item to classify it correctly into the simple machine categories.

 

Question 2. Fill in the blanks using the proper word and complete the statements.

 

Question 2.a. The .......... in the centre, the .......... on one side and the on the .......... other side make a lever of the first order.
Answer: Fulcrum, load and effort
In simple words: In a first-order lever, the fulcrum is positioned between the load and the effort.

🎯 Exam Tip: Understanding the positions of fulcrum, load, and effort is crucial for classifying levers.

 

Question 2.b. The .......... in the centre, the .......... on one side and the .......... on the other side make a lever of the second order.
Answer: Load, fulcrum, effort
In simple words: In a second-order lever, the load is located between the fulcrum and the effort.

🎯 Exam Tip: Remember the order of load, fulcrum, and effort for each lever class to accurately identify them.

 

Question 2.c. The .......... in the centre, the .......... on one side and the .............. on the other side make a lever of the third order.
Answer: Effort, fulcrum, load
In simple words: In a third-order lever, the effort is applied between the fulcrum and the load.

🎯 Exam Tip: Differentiate between the three orders of levers by memorizing the relative positions of the fulcrum, load, and effort.

 

Question 3. Which machines will you use to do the following work? Write their types.

 

Question 3.a. To remove the lid of a tin.
Answer:
• Work: To remove the lid of a tin.
• Machine: Opener
• Machine: Lever of the second order
In simple words: To open a tin lid, an opener is used, which acts as a second-order lever where the load (lid) is between the fulcrum and the effort.

🎯 Exam Tip: Clearly state both the machine used and its type (simple/complex and lever order) for full marks.

 

Question 3.b. To lift bricks to the top of a tall building.
Answer:
• Work: To lift bricks to the top of a tall building
• Machine: Crane
• Machine: Complex machine
In simple words: Lifting bricks to a height requires a crane, which is a complex machine composed of several simple machines working together.

🎯 Exam Tip: Recognize that complex tasks often involve complex machines, which are combinations of simple machines.

 

Question 3.c. To cut vegetable.
Answer:
• Work: To cut vegetable
• Machine: Knife
• Machine: Wedge - Simple machine
In simple words: A knife is used to cut vegetables and functions as a wedge, which is a type of simple machine.

🎯 Exam Tip: Identify common tools and classify them by the simple machine principle they utilize.

 

Question 3.d. To draw water from a well.
Answer:
• Work: To draw water from a well
• Machine: Pulley
• Machine: Simple machine
In simple words: A pulley is a simple machine used to change the direction of force, making it easier to draw water from a well.

🎯 Exam Tip: Explain how a pulley simplifies work by altering the direction of effort, rather than reducing the total force required.

 

Question 3.e. To hold a papad for roasting it.
Answer:
• Work: To hold a papad for roasting it.
• Machine: A pair of tongs
• Machine: Lever of the third order
In simple words: Tongs are used to hold papads while roasting, functioning as a third-order lever where the effort is applied between the fulcrum and the load.

🎯 Exam Tip: Practice identifying examples of third-order levers, often characterized by the effort being in the middle.

 

Question 4. Write the answers to the following questions in your own words.

 

Question 4.a. What is meant by a simple machine?
Answer:
1. Machines which have only one or two parts and a simple and easy structure are simple machines.
2. Example: the bottle opener, nail cutter.
3. Simple machines can be handled easily.
4. We use many simple machines in our day to day life.
In simple words: Simple machines are basic tools with few parts, designed to make everyday tasks easier and more efficient.

🎯 Exam Tip: Provide a clear definition and at least two relevant examples when asked about simple machines.

 

Question 4.b. Mention the advantages of using a machine.
Answer:
1. Machines, simple or complex, are used to get more work done in less time and with less effort.
2. Machines are used to accomplish certain tasks more easily.
3. Use of simple or complex machines depends upon the task to be carried out and the time and the efforts required to do it.
In simple words: Machines help us complete tasks faster and with less physical effort, simplifying work and improving efficiency.

🎯 Exam Tip: Focus on efficiency, time-saving, and effort reduction as key advantages of machines.

 

Question 4.c. What is meant by a complex machine?
Answer:
1. Complex machines have many parts which carry out many processes for completing a task.
2. For this purpose the parts are joined to one another.
3. Therefore, these machines are called complex machines.
4. Some of the parts of such complex machines are actually simple machines.
5. The structure of complex machine is complicated.
In simple words: Complex machines consist of multiple interconnected parts performing various processes to complete a task, often incorporating several simple machines.

🎯 Exam Tip: Highlight the multi-part structure and multiple processes as defining characteristics of complex machines.

 

Question 4.d. What is a lever? How is the order of the lever determined?
Answer:
1. Lever is a simple machine made up of 3 parts: Load, effort and fulcrum.
2. Order of the lever are determined on the position of the effort, the fulcrum and the load.
In simple words: A lever is a simple machine with three main components-load, effort, and fulcrum; its class depends on the arrangement of these three points.

🎯 Exam Tip: Always list the three components of a lever and explain how their relative positions define the lever's order.

 

Question 5. Why is this so?

 

Question 5.a. Traveller's bags have wheels.
Answer:
1. Combination of wheel and axle is a simple machine.
2. When the axle starts rotating due to force applied, the wheel fitted to it also starts rotating.
3. This makes easier for travellers to carry heavy load.
4. Instead of lifting heavy bag, to drawing it on wheels require less energy. Therefore, traveller's bag have wheels.
In simple words: Traveller's bags have wheels because the wheel and axle system is a simple machine that significantly reduces the effort needed to move heavy luggage, making transport easier.

🎯 Exam Tip: Connect the use of wheels on bags directly to the mechanical advantage provided by the wheel and axle, reducing effort and energy.

 

Question 5.b. Machines have to be maintained.
Answer:
1. Parts of machines rub against one another when they are used.
2. Soiled, dusty parts create more friction. Some parts are affected by the weather, rust and corrosion.
3. Machines get damaged or become useless due to such wear and tear. Hence to avoid this, machines should be maintained properly to keep them in good working condition.
In simple words: Machines need maintenance to prevent wear and tear from friction, dust, and weather, ensuring they remain functional and last longer.

🎯 Exam Tip: Emphasize friction, corrosion, and wear as key reasons for machine degradation and the importance of maintenance for longevity.

 

Question 5.c. A bicycle is said to be a complex machine.
Answer:
1. Bicycle has a complicated structure.
2. Bicycle has many parts which carry out many processes for completing a task.
3. Many parts of bicycle such as pedals, wheels, axle, handle are actually simple machines.
4. The parts of a bicycle are joined to one another - making it a complex machine.
In simple words: A bicycle is a complex machine because it combines multiple simple machines like pedals, wheels, and levers, all interconnected to perform the task of movement.

🎯 Exam Tip: When explaining complex machines, always mention that they are made up of multiple simple machines working together.

 

Question 6. Name the levers mentioned in the following passage. Identify the fulcrum, load and effort of each and say which type of lever it is. Ravi and Savita sit on a sea-saw in a garden. In the mean time, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.
Answer: Levers:
1. See saw - lever of the first order. Load - fulcrum - effort.
2. Wheelbarrow - lever of the second order. Fulcrum - load - effort.
3. Lemon squeezers - lever of the second order. Fulcrum - load - effort.
4. Tongs - lever of the third order. Fulcrum - effort - load.
In simple words: The passage describes a seesaw (first-order), a wheelbarrow and lemon squeezer (second-order), and tongs (third-order), each identified by the relative positions of their fulcrum, load, and effort.

🎯 Exam Tip: For passage-based questions, carefully read to identify each machine, then determine its type by analyzing the fulcrum, load, and effort positions.

 

Activity:

 

Question 1. Make a list of the various machines used in your home and neighborhood and write their types.
Answer: (Student's own observation and classification would be required here. Examples could include: Door - Lever, Scissors - Lever (First Order), Bottle opener - Lever (Second Order), Ramp - Inclined Plane, Bicycle - Complex Machine).
In simple words: This activity asks students to observe and list machines from their daily surroundings and classify them by type (simple or complex, and if simple, its specific category like lever, pulley, inclined plane, etc.).

🎯 Exam Tip: Practical application of concepts is important; try to identify at least 5-7 machines and correctly classify them.

 

Question 2. Go to a bicycle repair shop, observe how a bicycle is repaired, and note down the information.
Answer: (This is an observational activity, the answer will vary based on student's experience. It typically involves observing the use of wrenches, screwdrivers, pumps, etc., and how different parts of the bicycle are adjusted or replaced.)
In simple words: This activity encourages observing the repair process of a bicycle, noting the various tools used and how different parts, acting as simple machines, are fixed or replaced.

🎯 Exam Tip: Focus on identifying the simple machines (levers, screws, wrenches) used by the mechanic and how they simplify the repair tasks.

Class 6 Science Chapter 12 Simple Machines Important Questions And Answers

Fill In The Blanks.

 

Question 1. Simple machines can be handled ..........
Answer: easily
In simple words: Simple machines are easy to operate due to their straightforward design and few parts.

🎯 Exam Tip: For fill-in-the-blanks, choose the most appropriate and concise word that completes the statement accurately.

 

Question 2. The structure of complex machine is ..........
Answer: complicated
In simple words: Complex machines have intricate designs with many interconnected parts, making their structure complicated.

🎯 Exam Tip: Understand the difference between simple and complex machines, particularly regarding their structural complexity.

 

Question 3. The more gradual the the ............... lesser is the we bear. But, such an inclined plane is ..........
Answer: slope, weight, longer
In simple words: A more gradual slope on an inclined plane reduces the weight or effort needed, but requires a longer distance to move the object.

🎯 Exam Tip: Remember the inverse relationship: a gradual slope reduces effort but increases the distance covered.

 

Question 4. The steeper the .............., the .......... is the inclined plane. But we have to bear a .......... weight.
Answer: slope, shorter, greater
In simple words: A steeper inclined plane is shorter but requires greater effort or weight to move an object up.

🎯 Exam Tip: Contrast the properties of steep vs. gradual inclined planes, focusing on length, effort, and weight.

 

Question 5. A screw is like a rolled up inclined plane made of an .......... strip.
Answer: iron
In simple words: A screw fundamentally functions as an inclined plane wrapped around a central cylinder, often made from an iron strip.

🎯 Exam Tip: Visualize a screw as a helical inclined plane; this helps in understanding its mechanical advantage.

 

Question 6. A wedge is used for ......... an object into two pieces or to .............. the objects stuck together.
Answer: breaking, separate
In simple words: Wedges are simple machines designed to split objects apart (breaking) or to push two stuck objects away from each other (separate).

🎯 Exam Tip: Know the primary functions of a wedge: splitting, separating, or tightening.

 

Question 7. A farmer uses a strong ............. to remove the big stone bogged down in the farm.
Answer: crow-bar
In simple words: Farmers use a crow-bar, a type of lever, to apply significant force and lift heavy objects like large stones.

🎯 Exam Tip: Identify practical applications of simple machines in agriculture and daily life.

 

Question 8. A device with a grooved wheel and thread designed to lift weights is called a ..........
Answer: pulley
In simple words: A pulley is a simple machine featuring a grooved wheel and rope, primarily used to lift weights by changing the direction of applied force.

🎯 Exam Tip: Recall the definition and primary use of a pulley as a simple machine for lifting.

 

Question 9. When we use a pulley, force is applied in the downward direction for lifting the weight in an ............. direction.
Answer: upward
In simple words: A pulley allows you to apply force downwards to effectively lift a weight in an upward direction, making the lifting process more convenient.

🎯 Exam Tip: Understand how a pulley changes the direction of force, which is its main mechanical advantage.

 

Question 10. Combination of an axle and a wheel is a ............. machine.
Answer: simple
In simple words: The wheel and axle system is a fundamental simple machine used to multiply force or transmit rotational motion.

🎯 Exam Tip: Classify the wheel and axle as one of the six basic simple machines.

 

Question 11. A needle and a nail are also kind of ..............
Answer: wedge
In simple words: Needles and nails are examples of wedges, simple machines with a tapering shape used for piercing or splitting.

🎯 Exam Tip: Recognize that many pointed or tapered tools are variations of the wedge simple machine.

 

Question 12. Machines are covered when not in use to prevent ............. settling on them.
Answer: dust
In simple words: Covering machines when not in use protects them from dust accumulation, which can cause friction and damage.

🎯 Exam Tip: Remember dust as a common environmental factor that necessitates protective covering for machines.

 

Question 13. In Archimedes' screw, the pipe was placed at an angle of .......... with one end inside the .......... and the rod resting on a ..............
Answer: 45°, water, flat surface.
In simple words: Archimedes' screw functions by having a pipe set at a 45-degree angle, with one end submerged in water and a rotating rod resting on a flat surface to lift water.

🎯 Exam Tip: Recall the key structural details of Archimedes' screw, including the angle, water placement, and support surface.

Match The Columns:

 

Question 1.

Column 'A'	Column 'B'
1. Pair of Scissors	a. Third order of lever
2. Tongs	b. Second order of lever
3. Opener	c. First order of lever

Answer:

Column 'A'	Column 'B'
1. Pair of Scissors	c. First order of lever
2. Tongs	a. Third order of lever
3. Opener	b. Second order of lever

In simple words: Matching these simple machines to their lever types correctly classifies scissors as first order, tongs as third order, and openers as second order based on the fulcrum, load, and effort positions.

🎯 Exam Tip: To ace match-the-column questions, understand the principle of each lever type and associate them with common examples.

 

Question 2.

Column 'A'	Column 'B'
1. Inclined plane	a. Needle
2. Pulley	b. Screw
3. Wedge	c. Crane

Answer:

Column 'A'	Column 'B'
1. Inclined plane	b. Screw
2. Pulley	c. Crane
3. Wedge	a. Needle

In simple words: This matching exercise correctly links the inclined plane to a screw, a pulley to a crane, and a wedge to a needle, demonstrating various simple machine applications.

🎯 Exam Tip: Familiarize yourself with examples of each simple machine type to quickly match them in questions.

State Whether The Following Statements Are 'True' Or 'False'.

 

Question 1. Lever helps big vehicle to climb up and down the mountain easily.
Answer: False
In simple words: Levers are not typically used to help large vehicles navigate mountains; inclined planes (like roads) are more relevant for this purpose.

🎯 Exam Tip: Differentiate the primary functions of various simple machines to avoid common misconceptions.

 

Question 2. Combination of wheel and axle is a simple machine.
Answer: True
In simple words: The wheel and axle system is indeed classified as one of the fundamental simple machines.

🎯 Exam Tip: Memorize the list of basic simple machines, including the wheel and axle.

 

Question 3. In pulley, force can be applied in upward direction.
Answer: False
In simple words: While pulleys can change the direction of force, a single fixed pulley is typically used to apply a downward force to lift a weight upward.

🎯 Exam Tip: Understand that the primary benefit of a simple fixed pulley is changing force direction, usually making it more convenient by pulling downwards.

 

Question 4. Screw is an example of wedge.
Answer: False
In simple words: A screw is an inclined plane wrapped around a cylinder, not a wedge, which is a simple machine used to separate or split objects.

🎯 Exam Tip: Avoid confusing different simple machines; a screw is an inclined plane, while a wedge is typically two inclined planes joined back-to-back.

 

Question 5. In Archimedes screw, the rod rests on flat surface.
Answer: True
In simple words: In Archimedes' screw, the central rod is indeed supported by resting on a flat surface, allowing it to rotate efficiently.

🎯 Exam Tip: Recall the structural components and operation of Archimedes' screw, including how its parts are supported.

 

Question 6. A slanting plank is used to lift a weight.
Answer: True
In simple words: A slanting plank serves as an inclined plane, a simple machine that makes lifting weights easier by distributing the effort over a longer distance.

🎯 Exam Tip: Recognize that any sloped surface used to move objects to a different height acts as an inclined plane.

 

Question 7. A winding road or ghat is an example of lever of first order.
Answer: False
In simple words: Winding roads or ghats are examples of inclined planes, not first-order levers, as they reduce effort for climbing by increasing distance.

🎯 Exam Tip: Differentiate between inclined planes and levers, remembering that roads on hills primarily use the principle of an inclined plane.

Answer The Following Questions In One Sentence.

 

Question 1. What is a machine?
Answer: Devices which are used to get more work done in less time and less effort are called machines.
In simple words: A machine is a tool designed to simplify work by reducing effort or time needed for a task.

🎯 Exam Tip: A concise definition of a machine should highlight its purpose: making work easier or faster.

 

Question 2. What is a simple machine?
Answer: Machines which have only one or two parts and a simple and easy structure are called simple machines.
In simple words: Simple machines are basic devices with very few parts, designed to perform work using a single force or movement.

🎯 Exam Tip: Focus on the "few parts" and "simple structure" when defining a simple machine.

 

Question 3. What is a complex machine?
Answer: Some machines have many parts and they carry out many processes for completing a task. For this purpose, the parts are joined to each other. They are called complex machines.
In simple words: Complex machines are made up of many interconnected parts that work together through multiple steps to achieve a specific task.

🎯 Exam Tip: Emphasize "many parts" and "multiple processes" when defining complex machines.

 

Question 4. List the properties of simple machines.
Answer: Properties of simple machine are:
1. They are made up of only one or two parts.
2. They have a simple and easy structure.
3. They can be handled easily.
4. There are less chances of simple machines breaking down or getting damaged.
In simple words: Simple machines are characterized by having few parts, a straightforward structure, ease of use, and a lower likelihood of breakdown.

🎯 Exam Tip: List key features like simplicity, ease of use, and durability when describing properties of simple machines.

 

Question 5. List properties of complex machines.
Answer: Properties of complex machine are:
1. These machines have many parts to carry out many processes.
2. The parts are joined to one another.
3. The structure of complex machines is complicated.
4. Some parts of complex machines are actually simple machines.
In simple words: Complex machines have numerous interconnected parts, perform multiple processes, feature an intricate structure, and often integrate several simple machines.

🎯 Exam Tip: Focus on the complexity, interconnectedness, and multi-functional aspects when listing properties of complex machines.

 

Question 6. What is an inclined plane?
Answer: A slanting plank which is used to lift a weight on which we bear less weight and lifting becomes easier is an inclined plane.
In simple words: An inclined plane is a sloped surface that makes it easier to move objects to a higher elevation by spreading the effort over a greater distance.

🎯 Exam Tip: Define an inclined plane by its sloped nature and its mechanical advantage in reducing the effort for vertical movement.

 

Question 7. What is a screw?
Answer: A screw is like a rolled up inclined plane made up of iron strip.
In simple words: A screw is essentially an inclined plane wrapped around a central shaft, used to convert rotational motion into linear motion or provide strong fastening.

🎯 Exam Tip: Always describe a screw as an inclined plane in a spiral form when defining it.

 

Question 8. What is a wedge?
Answer: A wedge is used for breaking an object into two pieces or to separate objects stuck together.
In simple words: A wedge is a simple machine, usually triangular, used to split objects apart, hold them together, or lift them by applying force to its thick end.

🎯 Exam Tip: Emphasize the splitting or separating function of a wedge in its definition.

 

Question 9. State examples of wedges.
Answer: An axle, a knife, a chisel, a needle and a nail are different kinds of wedges.
In simple words: Common examples of wedges include tools like knives, chisels, needles, and nails, which all feature a tapered design for piercing or splitting.

🎯 Exam Tip: Provide diverse examples of wedges to demonstrate a comprehensive understanding of the concept.

 

Question 10. What is a lever?
Answer: A lever is a machine made up of 3 parts: effort, load and fulcrum.
In simple words: A lever is a rigid bar that rotates around a fixed point called a fulcrum, used to apply force to a load with less effort.

🎯 Exam Tip: Always include the three essential components - fulcrum, load, and effort - when defining a lever.

 

Question 11. What is a fulcrum?
Answer: The support at which the rod of a lever is rested is called fulcrum of a lever. The lever rotates about the fulcrum.
In simple words: The fulcrum is the fixed pivot point around which a lever rotates.

🎯 Exam Tip: Identify the fulcrum as the fixed pivot point, critical for a lever's operation.

 

Question 12. What is a load?
Answer: The weight lifted by a lever or the force against which the lever acts is called a load.
In simple words: The load is the object or resistance that a lever is used to move or overcome.

🎯 Exam Tip: Clearly define the load as the resistance being moved or acted upon by the lever.

 

Question 13. What is a load arm?
Answer: The arm of the lever from the fulcrum to the load is called a load arm.
In simple words: The distance between the fulcrum and where the load is placed on a lever is known as the load arm.

🎯 Exam Tip: Understanding the components of a lever (load, effort, fulcrum, and their respective arms) is crucial for classifying different lever types.

 

Question 14. What is an effort?
Answer: The force applied on the other end of the rod to lift the load is called an effort.
In simple words: Effort is the force you apply to a machine to do work, like pushing down on a lever to lift something.

🎯 Exam Tip: Clearly distinguishing between load and effort is fundamental to grasping how machines provide mechanical advantage.

 

Question 15. What is an effort arm?
Answer: The part of the lever from the fulcrum to the effort is called an effort arm.
In simple words: The effort arm is the distance from the fulcrum to where the effort is applied on a lever.

🎯 Exam Tip: The length of the effort arm relative to the load arm determines the mechanical advantage of a lever.

 

Question 16. What is lever of the first order?
Answer: The fulcrum is in the centre, the load is at one end while effort is at other end.
In simple words: A first-order lever has the fulcrum positioned between the effort and the load, like a seesaw.

🎯 Exam Tip: Remembering common examples like scissors or a seesaw helps to easily identify first-order levers in real-world scenarios.

 

Question 17. What is lever of the second order?
Answer: The load is in the centre, the fulcrum on one side, and the effort on the other side.
In simple words: In a second-order lever, the load is located between the fulcrum and the effort, such as a wheelbarrow.

🎯 Exam Tip: The load being between the fulcrum and effort is the defining characteristic of a second-order lever, always providing a mechanical advantage.

 

Question 18. What is lever of the third order?
Answer: The effort is in the centre, the fulcrum on one side, and the load on the other side.
In simple words: A third-order lever has the effort applied between the fulcrum and the load, like a pair of tongs.

🎯 Exam Tip: Third-order levers prioritize range of motion and speed over force, often seen in tools used for precision or dexterity.

 

Question 19. What is a pulley?
Answer: A pulley is a device with a grooved wheel and thread designed to lift weights.
In simple words: A pulley is a simple machine consisting of a grooved wheel and a rope or chain, used to change the direction or magnitude of a force for lifting objects.

🎯 Exam Tip: Pulleys are fundamental simple machines often used in combination to multiply force or change the direction of effort.

 

Question 2. How does a pulley help us?
Answer: If we use a pulley, force can be applied in the downward direction for lifting the weight in an upward direction. It is convenient and easy.
In simple words: Pulleys help us lift heavy objects by allowing us to apply force in a more convenient downward direction, making the lifting task easier.

🎯 Exam Tip: The primary advantage of a simple fixed pulley is changing the direction of force, making tasks more ergonomic and convenient.

 

Give Scientific Reasons:

 

Question 1. We use many simple machines in our day-to-day life.
Answer: Simple machines can be handled easily and there are less chances of these machines breaking down or getting damaged. Hence, we use many simple machines in our day-to-day life.
In simple words: We use simple machines daily because they are easy to operate, less prone to breaking, and make tasks simpler and faster to complete with less effort.

🎯 Exam Tip: Focus on the benefits of simple machines-ease of use, durability, and mechanical advantage-when explaining their widespread application.

 

Question 2. Less force is required to fit a screw than to hammer a nail.
Answer:
1. A screw is like a rolled-up inclined plane of an iron strip.
2. When a screw is fitted in wood it goes in as if it is going down an inclined plane.
3. Therefore, less force is required to fit a screw than hammer a nail.
In simple words: A screw acts as a winding inclined plane, reducing the force needed to penetrate a surface compared to the direct impact of hammering a nail.

🎯 Exam Tip: The principle of the inclined plane is key here; the longer the "path" (threads of the screw), the less force is needed to achieve the same result.

 

Question 3. Big vehicles easily climb up and down the mountains than a pathway.
Answer: A winding road or ghat that goes up a mountain is like an inclined plane wrapped around the mountain. It helps big vehicles to climb, up and down the mountain easily.
In simple words: Winding mountain roads, acting as inclined planes, allow large vehicles to climb with less effort over a longer distance, making ascent and descent safer and easier than a steep, direct pathway.

🎯 Exam Tip: Explain that a longer inclined plane reduces the required force, even though it increases the distance traveled, which is beneficial for heavy vehicles.

 

Question 4. Oil or lubricant is released between parts of machine.
Answer: Oil or lubricant is released between parts that rub against each other so that there is less friction between them and wearing is reduced.
In simple words: Oil and lubricants are used between machine parts to reduce friction, which prevents wear and tear and allows the machine to operate smoothly and efficiently.

🎯 Exam Tip: Highlighting the role of lubricants in friction reduction and machine longevity demonstrates a practical understanding of machine maintenance.

 

Question 5. Machines are covered when not in use.
Answer: Machines are covered when not in use to prevent dust settling on them.
In simple words: Covering machines when not in use protects them from dust accumulation, which can cause friction and damage to moving parts.

🎯 Exam Tip: Proper storage and protection from environmental factors are crucial aspects of machine maintenance, ensuring optimal performance and lifespan.

 

Question 6. How are machines protected from the effect of weather?
Answer: To prevent the effect of weather, metallic parts in a machine are painted externally and the machines are always kept dry.
In simple words: Machines are protected from weather effects by painting metallic parts to prevent rust and corrosion, and by keeping them dry to avoid moisture-related damage.

🎯 Exam Tip: Mentioning both protective coatings (paint) and environmental control (keeping dry) shows a comprehensive understanding of weather protection for machines.

 

Draw The Neat And Labelled Diagram Of Following:

 

Question 1. The screw as an inclined plane.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक पेंच को एक झुके हुए तल (inclined plane) के रूप में दर्शाता है। एक त्रिभुजाकार कागज की पट्टी (triangular piece of paper) को एक पेंसिल के चारों ओर लपेटकर दिखाया गया है, जिससे यह स्पष्ट होता है कि पेंच की चूड़ियाँ (screw threads) वास्तव में एक झुके हुए तल का ही घुमावदार रूप हैं। यह दर्शाता है कि पेंच कैसे कम बल का उपयोग करके वस्तु में प्रवेश करता है।
In simple words: A screw is essentially an inclined plane wrapped around a cylinder, allowing it to penetrate materials with less force over a longer distance.

🎯 Exam Tip: When asked to draw, ensure labels are clear and the diagram accurately represents the concept, like the helical path of a screw being an inclined plane.

 

Question 2. Archimedes' screw
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र आर्किमिडीज स्क्रू पंप को दर्शाता है, जो एक प्राचीन यांत्रिक उपकरण है जिसका उपयोग निचले स्तर से पानी को ऊपर उठाने के लिए किया जाता है। इसमें एक बड़े पाइप के अंदर एक हेलिक्स के आकार का घुमावदार पेंच होता है जिसे घुमाया जाता है। जैसे-जैसे पेंच घूमता है, यह पानी को अपने घुमावों के साथ ऊपर की ओर धकेलता है, जिससे पानी निचले स्रोत से ऊपर की ओर ले जाया जा सकता है।
In simple words: Archimedes' screw is a device with a rotating helical screw inside a cylinder, used to lift water or granular materials from a lower to a higher elevation.

🎯 Exam Tip: For historical or complex machines like Archimedes' screw, focus on describing its main components and how its unique design (the helix) achieves its primary function (lifting water).

 

Observe The Following Diagram And Identify The Order Of Lever.

 

Question 1. Removing the lid.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक बॉटल ओपनर का उपयोग करके बोतल का ढक्कन हटाने की प्रक्रिया को दर्शाता है। ढक्कन लोड है, ओपनर का सिरा जो ढक्कन के नीचे टिका है वह फुल्क्रम है, और हाथ द्वारा लगाया गया बल (effort) दूसरी तरफ है। यह एक द्वितीय श्रेणी का उत्तोलक है।
In simple words: The diagram shows a bottle opener removing a lid; the fulcrum is at one end, the load (lid) is in the middle, and the effort is applied at the other end, making it a second-order lever.

🎯 Exam Tip: Identify the positions of the fulcrum, load, and effort to correctly classify the lever order, using examples like bottle openers as second-order levers.

 

Question 2. Picking up an object.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक चिमटे (tongs) का उपयोग करके किसी वस्तु को उठाने की क्रिया को दर्शाता है। चिमटे का धुरी बिंदु फुल्क्रम है, वह स्थान जहाँ हाथ से दबाव डाला जाता है वह प्रयास (effort) है, और चिमटे के सिरे पर पकड़ी गई वस्तु लोड है। यह एक तृतीय श्रेणी का उत्तोलक है।
In simple words: This diagram illustrates using tongs to pick up an object, where the effort is applied between the fulcrum and the load, categorizing it as a third-order lever.

🎯 Exam Tip: Tools like tongs, where the effort is between the fulcrum and load, are classic examples of third-order levers, characterized by increased range of motion.

 

Question 3. Lifting a paper weight.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक रूलर या पट्टी का उपयोग करके एक पेपरवेट को उठाने की क्रिया को दर्शाता है। पेपरवेट लोड है, जहाँ रूलर किसी आधार पर टिका है वह फुल्क्रम है, और हाथ द्वारा रूलर के दूसरे सिरे पर लगाया गया बल (effort) है।
1. Lever of the second order
2. lever of third order
3. Level of first order.
In simple words: The diagram depicts lifting a paperweight with a lever. Depending on the relative positions of the load (paperweight), effort (hand), and fulcrum (pivot point), this setup can represent a first, second, or third order lever.

🎯 Exam Tip: To correctly classify a lever, precisely locate the fulcrum (pivot), the load (object being moved), and the effort (force applied).

 

Answer Each Of The Question In Brief:

 

Question 1. With the help of the diagram explain lever of the 1st, 2nd, 3rd order.
Answer:
1. Lever of the First order: The fulcrum is in the centre, the load is at one end, while the effort is at the other end. e.g. scissors
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक प्रथम श्रेणी के उत्तोलक को दर्शाता है, जहाँ आधार (fulcrum) लोड और प्रयास (effort) के बीच में स्थित होता है। तीर लोड और प्रयास की दिशा दिखाते हैं, जबकि फुल्क्रम स्थिर बिंदु है जिसके चारों ओर उत्तोलक घूमता है। कैंची इसका एक सामान्य उदाहरण है।
2. Lever of the Second order: The load is in the centre, the fulcrum on one side, and the effort on the other side. e.g. lid opener
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक द्वितीय श्रेणी के उत्तोलक को दर्शाता है, जहाँ लोड (वस्तु जिसे उठाया जा रहा है) आधार (fulcrum) और प्रयास (effort) के बीच में स्थित होता है। प्रयास आमतौर पर ऊपर की ओर होता है और लोड नीचे की ओर होता है, जबकि फुल्क्रम एक किनारे पर होता है। ढक्कन खोलने वाला उपकरण इसका एक उदाहरण है।
3. Lever of the Third order: The effort is in the centre, the fulcrum on one side, and the load on the other side. e.g. Tongs
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक तृतीय श्रेणी के उत्तोलक को दर्शाता है, जहाँ प्रयास (effort) आधार (fulcrum) और लोड (load) के बीच में स्थित होता है। इस प्रकार के उत्तोलक में, लोड को उठाने के लिए अधिक प्रयास की आवश्यकता होती है, लेकिन यह गति और दूरी में वृद्धि प्रदान करता है। चिमटा इसका एक उदाहरण है।
In simple words: Levers are classified into three orders based on the relative positions of the fulcrum, load, and effort. First-order has the fulcrum in the middle, second-order has the load in the middle, and third-order has the effort in the middle.

🎯 Exam Tip: When explaining lever orders, always provide clear diagrams with labeled fulcrum, load, and effort, along with a common example for each to illustrate the concept effectively.

 

Question 2. How can machines be maintained?
Answer:
1. To maintain machines, all its parts are wiped clean.
2. Oil or lubricant is released between parts that rub against each other.
3. Machines are covered, painted externally and always kept dry.
In simple words: Machines are maintained by regularly cleaning their parts, applying oil or lubricant to reduce friction, covering them to prevent dust accumulation, painting external metallic parts to prevent rust, and keeping them dry.

🎯 Exam Tip: A good answer on machine maintenance should cover cleaning, lubrication, and protection from environmental factors (dust, moisture, corrosion).

 

Question 3. What is an inclined plane? Explain longer and shorter inclined plane.
Answer:
1. A slanting plank used to lift a weight, is called an inclined plane. Because of inclined plane we will experience less weight and weight lifting become easier.
2. Longer inclined plane: When the inclined plane is longer, the slope is more gradual and lesser is the weight we bear.
3. Shorter inclined plane: When the inclined plane is shorter, the slope is steeper and greater is the weight we bear.
In simple words: An inclined plane is a slanting surface that makes lifting heavy objects easier by spreading the effort over a longer distance. A longer inclined plane has a more gradual slope, requiring less force, while a shorter one has a steeper slope, requiring more force.

🎯 Exam Tip: Emphasize the inverse relationship between the length/gradualness of an inclined plane and the effort required to move an object up it.

 

Question 6. Explain the working of a giant wheel.
Answer:
1. The giant wheel is fitted to a rod at its centre. This rod is called an axle.
2. When the axle starts rotating with the help of electricity the wheel fitted to it starts rotating.
3. This combination of an axle and a wheel is a simple machine.
In simple words: A giant wheel works as a wheel and axle system where a central axle, powered by electricity, rotates the large wheel, demonstrating a simple machine principle.

🎯 Exam Tip: When explaining the working of machines like a giant wheel, focus on identifying the core simple machine principles (e.g., wheel and axle) at play.

 

Observe And Discuss:

 

Question 1. Name the devices and discuss how they help.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): इस चित्र में विभिन्न सरल मशीनें दिखाई गई हैं: (1) सुई और धागा - कपड़ों की सिलाई के लिए; (2) ठेला (wheelbarrow) - सामग्री ढोने के लिए; (3) ढक्कन खोलने वाला (opener) - बोतलों के ढक्कन खोलने के लिए; (4) घिरनी (pulley) - बाल्टी उठाने के लिए; (5) कील कटर (nail cutter) - नाखून काटने के लिए; और (6) कुल्हाड़ी (axe) - लकड़ी काटने के लिए। प्रत्येक उपकरण एक विशिष्ट कार्य को आसान बनाने में मदद करता है।
1. Needle and thread - Stitching of clothes
2. Wheelbarrow - To carry materials.
3. Opener - To open the lids of bottles.
4. Pulley - To lift bucket
5. Nail cutter - To cut nails
6. Axe - To cut wood into small pieces
In simple words: The devices shown are a needle and thread for stitching, a wheelbarrow for carrying, an opener for lids, a pulley for lifting, a nail cutter for nails, and an axe for cutting wood; each helps perform specific tasks more easily.

🎯 Exam Tip: When listing devices and their uses, be precise in describing their function and briefly mention how they simplify the task.

 

Can You Tell?

 

Question 1. Observe the machines shown in the following pictures. For what purposes are they used? Can you name some other machines of this kind?
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): इस चित्र में पांच विभिन्न मशीनें दिखाई गई हैं: (1) मिक्सर ग्राइंडर - खाद्य पदार्थों को पीसने के लिए; (2) स्कूटर - सवारी करने और स्थानों तक पहुँचने के लिए; (3) साइकिल - सवारी करने और स्थानों तक पहुँचने के लिए; (4) सिलाई मशीन - कपड़े सिलने के लिए; और (5) व्हीलचेयर - विशेष रूप से विकलांग रोगियों को घूमने में मदद करने के लिए डिज़ाइन की गई है। ये सभी मशीनें दैनिक जीवन के कार्यों को सरल बनाती हैं।
1. Mixer grinder - To grind the foodstuffs
2. Scooter - To ride and reach places
3. Bicycle - To ride and reach places
4. Sewing machine - To stitch clothes
5. Wheel chair - Specially designed for handicapped patients to move around.
In simple words: The pictures show a mixer grinder for grinding food, a scooter and bicycle for transport, a sewing machine for stitching, and a wheelchair for mobility assistance, all designed to simplify various daily tasks.

🎯 Exam Tip: For observation-based questions, accurately identify each machine and clearly state its primary purpose, linking it to the concept of making work easier.

 

Question 2. Compare the pathway and a road, available to climb the mountain, the time and strength and your convenience, required to reach the mountain top.
Answer: We can reach the mountain top by climbing the pathway early than by the road. The time required is less but the strength required is more. The road is easy to walk and more time consuming.
In simple words: A direct pathway up a mountain is quicker but demands more strength, while a winding road is easier and less strenuous but takes more time to reach the top.

🎯 Exam Tip: When comparing, clearly list the advantages and disadvantages of each option (pathway vs. road) in terms of time, effort, and convenience.

 

Question 3. If the point of a needle or the edge of a knife become blunt, then the needle does not penetrate the cloth and the knife does not cut into the fruit. Why is this so?
Answer: The tip of the needle or the edge of a knife becomes blunt due to regular use. Both the knife and the needle lose their sharpness.
In simple words: A blunt needle or knife increases the contact area, reducing the pressure applied at a single point, which makes it harder for them to penetrate or cut effectively.

🎯 Exam Tip: Connect the concept of sharpness to the principle of pressure: a smaller contact area creates higher pressure, making cutting or piercing easier.

 

Use Your Brain Power!

 

Question 1. Which task can be done using a lever?
Answer: Task such as using a nut cracker, cutting paper with scissors, can be done using a lever.
In simple words: Levers are used for tasks like cracking nuts, cutting paper, lifting heavy objects, or prying things open, all by magnifying force or changing its direction.

🎯 Exam Tip: Give diverse examples of levers in daily life to show a broad understanding of their applications, focusing on how they help accomplish work.

 

Question 2. Some machines we use in our day to day life are shown in picture. What is the type in each of these?
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): इस चित्र में दैनिक जीवन में उपयोग की जाने वाली विभिन्न सरल मशीनें दर्शाई गई हैं: (1) ठेला (wheelbarrow), (2) प्लायर्स (pliers), (3) सीसॉ (seesaw), (4) ढक्कन खोलने वाला (opener), और (5) कैंची (scissors)। इन मशीनों में से प्रत्येक एक विशिष्ट प्रकार के उत्तोलक या अन्य सरल मशीन सिद्धांत का उदाहरण है।
- Wheelbarrow - Lever of the second order
- Pair of tongs - Lever of the first order
- See - saw - Lever of the first
- order Cutter - Lever of the second lever
- Pair of Scissors - Lever of the first order.
In simple words: The machines shown include a wheelbarrow (second-order lever), pliers (first-order lever), seesaw (first-order lever), opener (second-order lever), and scissors (first-order lever), each categorized by the position of its fulcrum, load, and effort.

🎯 Exam Tip: For identifying lever types, clearly state the classification (e.g., first order) and briefly explain why, based on the fulcrum, load, and effort positions.

 

Question 3. When the pedal of the bicycle is rotating, the wheel starts rotating. How does this happen?
Answer: Pedals of the bicycle are connected to the wheels through the axle, when the axle starts rotating, the wheels also start rotating.
In simple words: A bicycle's pedals are connected to the wheel via a chain and gears, causing the axle to rotate when pedaled, which in turn makes the wheels rotate.

🎯 Exam Tip: Explaining the chain of action - pedals to chain, chain to gear, gear to axle, axle to wheel - demonstrates a clear understanding of the mechanical linkage.

 

Question 4. Examples of pulley.
Answer:
1. A simple pulley is used to hoist a flag, to draw water from a well.
2. The crane which is used to lift heavy loads is an example of application of pulleys and levers working together.
In simple words: Pulleys are used to hoist flags, draw water from wells, and are integral components in cranes for lifting heavy loads, often working with levers.

🎯 Exam Tip: Provide diverse examples, from simple daily uses to complex industrial applications, to show the versatility of pulleys.