CBSE Class 6 Science Force And Pressure Worksheet

Learning Objectives
1. Introduction
2. Force
3. Effects of force
4. Types of force
5. Thrust and Pressure
6. Pressure in fluids
7. Factors affecting pressure in fluids
8. Atmospheric pressure

INTRODUCTION
It is our common experience that to move a stationary table, we need to push it or pull it. To stop a moving ball we have to apply some force opposite to its
direction of motion. If the object is quite heavy it may not be set into motion by a force. A heavy object in motion may not be brought to rest on applying force on it. Thus based on these observations we can now define force.

FORCE
Force is defined as an external agent (push or pull) that changes or tends to change the state of rest or of uniform motion of a body.
Mathematical definition of force - Whenever force acts on a moving body it changes the speed of the body. Thus force produces acceleration (Positive or negative). Greater the force, greater is the acceleration. Also more the mass of the body, more is the force required to produce acceleration in it. Hence force is directly proportional to the mass and acceleration of the body.
                         Force = mass×acceleration
                                        F = ma
Thus, mathematically force is defined as the product of mass and acceleration. When a body falls under the force of gravity. Then, the force exerted on the earth is equal to the weight of that body i.e. W = m × g. Where, g = acceleration due to gravity g = 9.8 m/sec2 on the surface of the earth at mean sea level.
Do You Know : Acceleration due to gravity on the surface of the earth (9.8 ms²) is 6 times the acceleration due to gravity on the surface of moon (1.63 ms²).

Units of force
The S.I. unit of force is newton (N)
1 newton force moves a body of mass 1 kg with an acceleration of 1 m/s²
C.G.S. unit of force is dyne.
1 dyne force moves a body of mass 1 g with an acceleration of 1 cms^–2,

Relationship between newton and dyne
Using F = ma
1 N =1 kg × 1 m/s²
= 1000 g × 100 cm/s²
= 100000 gcm/s²
Since 1 dyne = 1 g cm/s²
∴ 1 N = 10⁵ dynes

EFFECTS OF FORCE
Force can bring about the following effects :
(1) Sets a body at rest into motion - If we apply force on a stationary car in the forward direction it can start moving.
(2) Stops a moving body - A ball falling downwards can be caught by our hands. Thus it stops on applying force
(3) Changes the speed of a moving body - A moving bicycle can be made to run faster on applying force on its paddles. A moving car can be slowed down by applying force using brakes.
(4) Changes the direction of motion of a body - The direction of a moving car can be changed by applying force on its steering wheel. A football player changes the direction of motion of the football by kicking it.
(5) Changes the dimensions of a body - Length of a spring can be increased or decreased by stretching or compressing it. Wet clay can be moulded to any shape by applying force with our hands.
Thus in brief we can say that force can change the state of rest or of  uniform motion of a body, can change the speed and direction of a moving body and can change the dimensions of a body.

TYPES OF FORCE
Force can be classified as follows:

Do You Know : There are four fundamental forces in nature the gravitational force, the electromagnetic force, the nuclear force and the weak force. Among these gravitational force is the weakest force.
Now, let us discuss these forces one by one.
(i) Contact forces - Forces which act only when two bodies are in contact with each other are called contact forces. Contact forces cannot act from a distance. For e.g., Force of friction acts only when two surfaces are in contact with each other. Push, pull, tension, force of friction and muscular force are examples of contact forces.
(a) Force of friction - An opposing force that acts when a body moves or tries to move over the surface of another body. Force of friction decreases the speed of a moving body.
(b) Muscular force - The force caused by the action of muscles in our body is known as muscular force. Lifting a load, pulling or pushing an object requires muscular force.
(ii) Non-contact forces - Forces applied by one body on another without being in actual contact are called non-contact forces. Non-contact forces act from a distance. For e.g. - An apple falls down due to the force of gravity acting on it from a distance. Force between magnets and magnetic materials (magnetic force), force between electric charges (electrostatic force) and nuclear force are all non-contact forces.
(a) Gravitational force - Force of attraction between any two masses is called gravitational force. For e.g., All objects on Earth experience force of gravity due to earth. It is always attractive in nature.
(b) Magnetic force - The force of attraction or repulsion between the poles of magnets is called magnetic force. Like poles repel each other and unlike poles attract each other.
(c) Electrostatic force - The force of attraction or repulsion between charged particles at rest is called electrostatic force. Like charges repel each other and unlike charges attract each other.

Balanced and unbalanced condition of forces
When two or more forces acting on an object cancel each other’s effect, then they are called balanced forces. If the forces on an object are balanced, then the net force on the object is zero. Thus the balanced forces do not cause any change in the object’s state of rest or of uniform motion.
Example: Two students pushing a table in opposite directions, each applying an equal amount of force, form a pair of balanced forces. Similarly in a tug of war if two teams pull the rope with equal force, then the rope stays in same place.
When two or more forces acting on a body do not cancel the effect of each other, they are called unbalanced forces. Unbalanced forces always cause change in the state of rest or of motion.
Example: A ball hit by a bat, someone moving the furniture etc. are due to unbalanced forces.

THURST AND PRESSURE
A force which acts normally on a surface is called thrust.
Force acting normally (perpendicular) i.e., thrust per unit area is called pressure.
If F is the force acting on area A, then
            Pressure = Thrust/Area
                        P = F/A
Thus smaller is the area on which the given force acts, the greater is the impact of force i.e. pressure and vice-versa.
(Remember : Force acting at an angle does not exert pressure on the surface)
Do You Know : Camels have broad feet, so that area ofcontact is high and pressure is less and they are able to walk on sand without sinking in it.

Unit of Pressure
The S.I. unit of pressure is Pascal (Pa). Pascal can be defined using the equation.
P = F/A                                            1Pa = 1N/1m
When a force of 1N acts normally on a surface of area 1 m2, then the pressure acting on the surface is called 1 Pascal.

Example based on pressure – area relation
(1) The bags and suitcases are provided with broad handles so that less pressure is exerted on our hands or shoulders while carrying them because more the area, less will be the pressure.
(2) Railway lines are laid on large sized wooden or concrete tracks so that the normal force due to the weight of the train spreads over a greater area thereby reducing the pressure on the ground. This prevents the yielding of ground.
(3) Dams are made thicker at the bottom in order to withstand the high pressure of water at the bottom.
(4) Pins and nails are pointed at one end to have least area of contact with the surface. Due to this on pressing, the pins exert high pressure on the surface and hence easily penetrate the surface.

PRESSURE IN FLUIDS
All liquids and gases are regarded as fluids as they can flow.
A fluid has weight and hence on account of its weight, it exerts pressure on the walls of the container. Moreover, unlike solids a fluid exerts pressure in all directions.
For instance if two holes are drilled in a bottle filled with water, it starts pouring out. This shows that water exerts pressure on the walls i.e., in all directions of the bottle or container.
Do You Know : Water pressure 10,000m below the surface is equivalent to seven elephants standing on a dinner plate

Factors affecting pressure in fluids
(1) Pressure in fluids is directly proportional to its height or depth in the container. Thus pressure at various points but same height will be equal.
For e.g., If 3 holes in a bottle of water are drilled at the same level from its base water will come out of all the three holes with equal pressure.
Also pressure below the liquid surface goes on increasing with depth.
(2) Pressure depends directly on the density ‘r’ of the fluid — A denser fluid exerts greater pressure.
(3) Pressure in a fluid is directly proportional to the acceleration due to gravity ‘g’
Thus, pressure P = hrg

Applications of pressure in fluids
(1) Deep sea divers wear special suits to bear higher pressure at greater depths.
(2) The water tank in a house is at the highest possible level so that the water pressure is more on the tap of the lowest level.
(3) Blood pressure in humans is greater at the feet than at the brain because height of the blood column is more at the feet than at the brain.

ATMOSPHERIC PRESSURE
The thrust due to the air column on a unit surface area of the earth is called atmospheric pressure.
Atmospheric pressure is measured by a barometer. A barometer using a liquid is known as liquid barometer. If a gas (air) is used, then it is known as aneroid barometer.
Atmospheric pressure on the sea level is 1.013 × 105 Pa.
Atmospheric pressure varies with the variation in height, season, temperature etc.
Do You Know : The sudden fall in atmospheric pressure produces the possibility of a storm.

Applications of atmospheric pressure
(1) Fountain pens leak on higher altitudes as the atmospheric pressure is less. Due to this the air within the tube of the fountain pen exerts pressure and forces the ink out.
(2) Sucking drink with the help of a straw is also based on atmospheric pressure. When we suck the air, the pressure inside the straw falls. The atmospheric pressure acting on the drink forces, it to rise in the straw.
(3) Astronauts wear special suit in space. It is because there is no
atmospheric pressure in space. But the internal pressure of blood is very high. Due to this pressure difference the blood vessels will burst. So they wear special space suits.
(4) Two holes are made in a sealed oil cane. Through one hole the atmospheric pressure acts which forces the oil to come out from the other hol
Do You Know : The pressure of the air on the outside of your body is balanced by the pressure of fluids inside.

More Question-

1. If Ravi pulls a cart by applying force 300 newton and Deepak pulls with a force of 200 newton. What will be the net resultant force.

2. An elephant weighing 40,000 newton stands on one foot of area 1000 m²(=1/10 m²).
What pressure is exerted on the ground?

3. What is the pressure exerted by a girl weighing 400 newton standing on one `stiletto` heel of area 1cm²(=1/10,000 m²)?

4. Compare the answers of question 2 and 3, which exerts more pressure per unit volume and why? Explain.

5. What is the magnitude of force required in newtons to produce a pressure of 26500 Pa on an area of 100 cm² ?

6. A force of 100 newton can produce a pressure of 100,000 Pa. Calculate the area in cm2 on which the force acts.

Multiple Choice Questions

Question. Force is a
(a) push
(b) pull
(c) both (a) and (b)
(d) none of these
Answer : C

Question. The CGS unit of force is
(a) newton
(b) pascal
(c) dyne
(d) None of these
Answer : C

Question. When a force of 10 N is applied on a body it starts moving with a constant acceleration of 2 m/s². The mass of the body is  
(a) 2 kg
(b) 0.2 kg
(c) 20 kg
(d) 5 kg
Answer : D

Question. 1 newton = ___________ dynes.
(a) 103
(b) 104
(c) 105
(d) 106
Answer : C

Question. When a cricketer catches the ball by his hands the force/forces coming in action is/are
(a) non-contact force
(b) gravitational force
(c) frictional force
(d) both (b) and (c)
Answer : D

Question. Force per unit area is ___________ .
(a) thrust
(b) pressure
(c) buoyancy
(d) density
Answer : B

Question. As we go to the higher altitude the atmospheric pressure ___________ .
(a) increases
(b) remain same
(c) decreases
(d) cannot say
Answer : A

Question. A stone falling from the roof of a house due to
(a) gravitational force
(b) magnetic force
(c) frictional force
(d) electrostatic force
Answer : A

Question. Pascal is equal to:
(a) N/m²
(b) N/m × s
(c) N/cm²
(d) N.m²
Answer : A

Question. Two stones A and B of masses 2 kg and 5 kg respectively are released from same height in vacuum. Which will reach on the ground first?
(a) Stone A
(b) Stone B
(c) Both will reach at same time
(d) None of these
Answer : C

Question. Electrostatic force is a
(a) contact force
(b) non-contact force
(c) balanced force
(d) unbalanced force
Answer : B

Question. How much pressure will be applied on a body.
If a force of 4 N is applied on its unit surface area. [Hint: Area = 1 m²]
(a) 0.25 Pa
(b) 2 Pa
(c) 8 Pa
(d) 4 Pa
Answer : D

Question. Which instrument is used for measuring atmospheric pressure?
(a) Hygrometer
(b) Barometer
(c) Hydrometer
(d) Sphygmomanometer
Answer : B

Question. A fluid is a substance that
(a) has no definite shape
(b) has no definite volume and shape
(c) has no definite volume
(d) is a liquid
Answer : B

Question. A force of 12 N is acting perpendicular on a wooden block. What will be the thrust on it?
(a) 12 N
(b) 24 N
(c) 48 N
(d) 6 N
Answer : A

Question. Pressure is the ratio of force to the __________ over which it is applied.
(a) surface
(b) volume
(c) distance
(d) area
Answer : D

Question. Force has
(a) only direction
(b) only magnitude
(c) both magnitude and direction
(d) neither magnitude nor direction
Answer : C

Question. Pressure is directly proportional to
(a) density
(b) height/depth
(c) acceleration due to gravity
(d) all of these
Answer : D

Question. Which of the following is an example of contact force?
(a) Magnetic force
(b) Gravitational force
(c) Electric force
(d) Muscular force
Answer : D

Question. The SI unit of force is
(a) newton
(b) dyne
(c) pascal
(d) none of these
Answer : A

Question. A mass of 2 kg is accelerated at 2 m/sec². Find the force applied on it.
(a) 4 N
(b) 1 N
(c) 8 N
(d) 0 N
Answer : A

Question. A stone of mass 4 kg is dropped from a height.
Find the force exerted by it on ground if acceleration due to gravity is 10 m/s2.
(a) 20 N
(b) 2.5 N
(c) 40 N
(d) 0.4 N
Answer : C

Match the Column

DIRECTIONS : Match Column-I with Column-II and select the correct answer using the codes given below the columns.

Question.
Column I                                  Column II
A. Thrust                                   (p) F/A
B. Pressure                               (q) Force
C. Atmospheric pressure           (r) Decrease with altitude
D. liquid pressure                      (s) Monometer
(a) A → (q); B → (p); C → (r); D → (s)
(b) A → (r); B → (p); C → (q); D → (s)
(c) A → (p); B → (r); C → (s); D → (q)
(d) A → (s); B → (q); C → (p); D → (r)
Answer : A

Question.
Column I                             Column II
A. Force                               (p) unit of force
B. Contact force                  (q) magnetic force
C. Non-contact force           (r) frictional force
D. Newton                           (s) mass × acceleration
(a) A → (q); B → (p); C → (r); D → (s)
(b) A → (r); B → (p); C → (q); D → (s)
(c) A → (p); B → (r); C → (s); D → (q)
(d) A → (s); B → (r); C → (q); D → (p)
Answer : D

Question.
Column I                              Column II
A. Acceleration                     (p) Contact force
B. Pressure                          (q) No atmospheric pressure
C. Space                              (r) Force/mass
D. Muscular force                (s) Barometer
(a) A → (q); B → (p); C → (r); D → (s)
(b) A → (r); B → (s); C → (q); D → (p)
(c) A → (p); B → (r); C → (s); D → (q)
(d) A → (s); B → (r); C → (q); D → (p)
Answer : B

Passage Based Questions

DIRECTIONS : Read the passage given below and answer the questions that follow.

Passage
Liquid pressure in a container doesn’t depend on the shape of the container but it ony depends on the height of the liquid column. The pressure due to a liquid at a point at a depth h from the surface of the liquid is given by P = rgh where, r is the density of the liquid and g is the acceleration due to gravity.

Question. A cylinderical container is full of water. The pressure at the bottom is P. Now, the water is replaced by cooking oil of density twice the
density of water. The new pressure at the bottom is
(a) 4 P
(b) 2 P
(c) 1.5 P
(d) 3 P
Answer : B

Question. If half of the water is taken out, what is the pressure at the bottom?
(a) P
(b) (1/2)P
(c) (3/2)P
(d) 2 P
Answer : B

Question. If the container is carried on a mountain then what will be the pressure at the bottom?
(a) less than P
(b) more than P
(c) equal to P
(d) None of these
Answer : A

Assertion/ Reason Based Questions

DIRECTIONS : The questions in this segment consists of two statements, one labelled as “Assertion A” and the other labelled as “Reason R”. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Question. Assertion (A) : Steel nails are pointed at one end to have least area of contact with surface.
Reason (R) : Least area exerts high pressure.
Answer : A

Question. Assertion (A) : Magnetic force is a non-contact force.
Reason (R) : Unlike poles of magnet attracts each other.
Answer : B

Question. Assertion (A) : A moving toy car stops after a little distance.
Reason : Friction opposes the motion.
Answer : A

Question. Assertion (A) : Apple falls on the ground, due to gravitational force.
Reason (R) : Gravitational force is a contact force.
Answer : C

Question. Assertion (A) : Sea divers wear special suits.
Reason (R) : There is no effect of gravity under the sea.
Answer : C

Question. Assertion (A) : Fluid exerts pressure on the walls of container.
Reason (R) : Fluids have definite shape and size.
Answer : C

Question. Assertion (A) : There is high atmospheric pressure in the space.
Reason (R) : Astronauts wear special suits.
Answer : D

Question. Assertion (A) : When a stone is thrown vertically upward, after getting a certain height it comes back to the earth.
Reason (R) : Stone has to work against the force of friction of air.
Answer : B

Statement Based Questions

DIRECTIONS : Read the following two statements carefully and choose the correct options.
(a) Statement (1) is correct while statement (2) is incorrect.
(b) Statement (2) is correct while statement (1) is incorrect.
(c) Both statements are correct
(d) Both statements are incorrect.

Question. Statement-1 : When one body moves or tries to move on the surface of another body, its speed continuously decreases.
Statement-2 : Friction is a contact force.
Answer : C

Question. Statement-1 : Atmospheric pressure increases with increase in depth of sea.
Statement-2 : Pressure is directly proportional to depth/height.
Answer : C

Question. Opening a door is an example of
(a) contact force
(b) non-contact force
(c) magnetic force
(d) balanced force
Answer : A

Question. A force F₁ acting on a body of 2 kg produces an acceleration of 2.5 m/sec². Another force F₂ acting on the body of mass 5 kg produces an acceleration of 2 m/sec². Find the ratio of F₂/F₁.
(a) 2
(b) 4
(c) 6
(d) 8
Answer : A

Question. An astronaut with all her equipment has a mass of 95 kilograms. How much will the weight on the moon, where the acceleration due to gravity
is 1.67 ms^–2?
(a) 159 N
(b) 169 N
(c) 149 N
(d) 100 N
Answer : A

Question. What force is needed to a accelerate a 60 kg wagon from rest to 5.0 ms–2 in 2.0 seconds?
(a) 100 N
(b) 120 N
(c) 150 N
(d) 130 N
Answer : C

Question. When a body is said to be under balanced forces then the resultant force applied on the body is
(a) one
(b) infinite
(c) zero
(d) none of these
Answer : C

Question. The pressure exerted by a column of liquid is independent of the __________.
(a) density of the liquid
(b) weight of the liquid
(c) depth of the liquid
(d) shape of the container
Answer : D

Question. A 500 kg rocket is fired straight up from the earth, the engine providing 7500 newton of thrust. Its acceleration is
(a) 4.5 m/s²
(b) 5.2 m/s²
(c) 9.8 m/s²
(d) 15 m/s²
Answer : D

Question. When a body is stationary
(a) there is no force acting on it
(b) the force acting on it not in contact with it
(c) the combination of forces acting on it balances each other
(d) the body is in vacuum
Answer : C

Question. What force would be required to produce an acceleration of 4 m/s² in a moving wall of mass 6 kg?
(a) 1.2 N
(b) 1.5 N
(c) 24 dynes
(d) 24 N
Answer : D

Question. Two forces 200 N and 300 N acting on a body in same direction. What is resultant force?
(a) 1.5 N
(b) 100 N
(c) 0.66 N
(d) 500 N
Answer : D

Question. Two bodies of masses m and 6m are moving under same magnitude of force. The ratio of their accelerations will be
(a) 1 : 6
(b) 6 : 1
(c) 1 : 36
(d) 36 : 1
Answer : B

Question. When an object is at rest on a surface - what can be said about the forces on it?
(a) they all are equal
(b) they are unbalanced
(c) there are not acting on it
(d) all the forces cancel out
Answer : D

Question. What is the surface area of tabletop if a force of 120 N exerted on it produces a pressure of 20 Pa?
(a) 2400 m²
(b) 60 m²
(c) 6 m²
(d) 240 m²
Answer : C

Question. The pressure at a point in a liquid is proportional to the __________ of the liquid and the depth of the point.
(a) density
(b) force
(c) area
(d) gravitational acceleration
Answer : A

Question. Gaurav wants to accelerate a body of mass 2 kg at 10 m/sec². On the other hand, Sahil wants to get accelerate a body of mass 5 kg at 2.5 m/sec². Who will need to apply more force?
(a) both will apply same force
(b) Gaurav
(c) Sahil
(d) none of these
Answer : B

Question. Stones A, B, C and D of same masses are thrown on a wall. Acceleration produced in them are 2 m/sec², 3 m/sec², 5 m/sec², 4 m/sec² respectively. Arrange the force exerted by the stones in descending order.
(a) fA > fB > fC > fD
(b) fD > fC > fB > fA
(c) fA > fB > fD > fC
(d) fC > fD > fB > fA
Answer : D

Question. The pressure of the water at the bottom of the pond is __________ at the surface of the pond.
(a) lower than
(b) same
(c) higher than
(d) either lower or higher
Answer : C

Question. If a pressure of 8 Pa acts on the surface of area 2m², then the force acting on the surface is
(a) 10 dynes
(b) 4.00 N
(c) 16 N
(d) 4.00 dynes
Answer : C

Question. What will be the change in acceleration of a sliding brick, if its mass is doubled, while a constant force is acting on it. Acceleration will be
(a) 2a
(b) a/2
(c) a/4
(d) 4a
Answer : B

Question. A car of mass 1000 kg can produce an acceleration of 8 m/s². Calculate the force produced by the engine ignoring friction.
(a) 10,000 N
(b) 100,000 N
(c) 8000 N
(d) 18000 N
Answer : C

Match the Column

DIRECTION : Match Column-I with Column-II and select the correct answer using the code given below the columns.

Question.
Column-I                      Column-II
A. dyne/cm²                 (p) 760 mm of Hg
B. 76 cm of Hg             (q) Nm^–2
C. 1 Pa                         (r) 1.013 × 10^–5 Nm^–2
D. 1 atm                       (s) 10^–1 Nm^–2
(a) A → (q); B → (p); C → (r); D → (s)
(b) A → (r); B → (p); C → (q); D → (s)
(c) A → (p); B → (r); C → (s); D → (q)
(d) A → (s); B → (p); C → (q); D → (r)
Answer : D

Question.
Column-I                                                           Column-II
A. Fielder stoping a ball                                     (p) Lifting
B. Opening a door                                             (q) Muscular force
C. Shutting a door                                              (r) Pulling
D. Drawing a bucket of water from a well          (s) pushing
(a) A → (q); B → (p); C → (r); D → (s)
(b) A → (r); B → (p); C → (q); D → (s)
(c) A → (q); B → (r); C → (s); D → (p)
(d) A → (s); B → (r); C → (q); D → (p)
Answer : C

Passage Based Questions

DIRECTIONS : Read the passage given below and answer the questions that follow.

Passage
Pressure is defined as the force exerted over a unit of area.
Pressure = area/force
Place a book on a bathroom scale and, whether you place it on its back, on its side, or balanced on a corner, it still exerts the same force. The weight reading is the same. Now balance the book on the palm of your hand and you sense a difference – the pressure of the book depends on the area over which the force is distributed.

Question. Which book will exert more pressure?
(a) Book 1
(b) Book 2
(c) Both exert equal pressure
(d) Can’t be determined
Answer : B

Question. If a force of 20N is applied on the surface of area 0.1 m2 then pressure experienced is
(a) 5 N/m²
(b) 100 N/m²
(c) 200 N/m²
(d) None of these
Answer : C

Assertion/ Reason Based Questions

DIRECTIONS : The questions in this segment consists of two statements, one labelled as “Assertion A” and the other labelled as “Reason R”. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Question. Assertion (A) : The acceleration produced by a force in the motion of a body depends only upon its mass.
Reason (R) : Larger is the mass of the body, lesser will be the acceleration produced.
Answer : A

Question. Assertion (A) : If the net external force on the body is zero, then its acceleration is zero.
Reason (R) : Acceleration does not depend on force.
Answer : C

Question. Assertion (A) : An object can move with constant velocity if no net force acts on it.
Reason (R) : No net force is needed to move an object with constant velocity.
Answer : A

Question. Assertion (A) : A body is momentarily at rest when it reverses the direction.
Reason (R) : A body cannot have acceleration if its velocity is zero at a given instant of time.
Answer : C

Statement Based Questions

DIRECTIONS : Read the following three statements carefully and choose the correct option.
(a) Statement (1) and (3) are incorrect while statement (2) is correct.
(b) Statement (1) and (2) are incorrect while (3) is correct.
(c) All the statements are correct.
(d) All the statements are incorrect.

Question. Statement-1 : It is easier to push a nail into a wooden box by the pointed end.
Statement-2 : Nail’s head is easier to hit.
Statement-3 : Pressure applied on all nails is same whatever is their size.
Answer : A

Question. Statement-1 : Porters place a round piece of cloth on their heads.
Statement-2 :Pressure is inversely proportional to area on which it acts.
Statement-3 :Pressure is independent of area of surface in contact.
Answer : A

Figure Based Questions

Question.

In which condition the wooden block will move?
(a) A
(b) B
(c) both A and B
(d) None of these
Answer : A

Question. Rajiv pulls a wooden box from one end with a force of 20 N, and Saurabh starts pushing the same box from opposite end with a force of 15 N. If a resultant acceleration of 2m/sec2 creates in the wooden box. Find the mass of the wooden box.
(Hint: Resultant of the force in the same direction is addative)

(a) 5 kg
(b) 70 kg
(c) 2.5 kg
(d) 17.5 kg
Answer : D

Question. Twinkle throws a stone of mass 1 kg in vertically upward direction. It’s velocity continuously decreases. After attaining a certain height its velocity becomes zero and it starts falling towards earth under gravitational force. If the acceleration due to gravity working on it is 10 m/sec². Then, how much force will it exert on ground, when it will strike to the ground?

(a) 10 N
(b) 20 N
(c) 0.1 N
(d) 100 N
Answer : A

Question. Rahul starts drilling a steel nail in a wooden block with its sharp side. The area of sharp side is 0.1 m². He applies a force of 2N on it. How much pressure will the nail exert on the wooden block?

(a) 2 Pa
(b) 0.2 Pa
(c) 20 Pa
(d) 200 Pa
Answer : C

Question. The diagram below shows two dogs pulling on a rope with constant but unequal forces

In which compass direction will both dogs most likely move?
(a) east
(b) west
(c) north
(d) south
Answer : A

Question. Name the device in the diagrams used to measure force.

(a) spring scale
(b) voltmeter
(c) thermometer
(d) graduated cylinder
Answer : A