Maharashtra Board Class 6 Science Chapter 10 Force and Types of Force PDF Download

10. Force and Types of Force

10.1 Various Actions

Will a boat move ahead unless pushed with the help of an oar?

Who exerts force to move a bullock-cart forward?

What makes the ball move during a game of football? How does its direction change?

Will the wheel go forward if it is not pushed with a stick?

When we kick the football coming in our direction, towards the goal, we apply force. In day-to-day life, we do many actions such as lifting, pulling, riding a bicycle and stopping it at times, pushing a load, squeezing or bending something and driving vehicles. It is necessary to apply force for doing all these actions. Force is applied to an object to pull it or push it in any manner.

No object changes its position on its own. Force is required to move an object. Force is used to change the direction of an object in motion, or to stop it.

Teacher's Note

Every day we use force when we play games, ride a cycle, or push a door. Force is everywhere in our life.

Exam Trick

Remember: Force means push or pull. Without force, nothing moves. Write this in your exam.

Points to Remember

Force is a push or a pull.
Force makes things move.
Force can change the direction of something moving.
Force can stop something that is moving.
Every action needs force.

10.2 Changing the Shape of an Object

What happens when you hold the two ends of a spring and pull them apart?

What happens when a blacksmith hammers a red hot piece of iron?

Force is necessary to change the shape an object.

Teacher's Note

When you squeeze a soft toy or bend a stick, you are using force to change its shape. This happens all around us.

Exam Trick

Remember: Force changes shape = Deform. When you squeeze clay, it changes shape because of force you apply.

Points to Remember

Force can change the shape of objects.
Pulling a spring makes it longer.
Pushing clay makes it flat.
Bending something changes its shape.
Not all objects change shape the same way.

Types of Force

1. Muscular Force

In all the actions shown in the picture 10.1, the movements take place with the help of the bones and muscles in the body. The person in the picture alongside is lifting the weight by using muscular force.

The force applied with the help of muscles is called muscular force.

For which tasks in your day-to-day life do you use muscular force?

Teacher's Note

We use muscular force when we carry our school bag, play sports, or help our parents at home. Our muscles give us the power to do these things.

Exam Trick

Remember: Muscular = Muscle. Your body muscles create this force. When you lift something, you use muscular force.

Points to Remember

Muscles in our body create muscular force.
We use muscles to lift and pull things.
Running, jumping, and playing use muscular force.
Animals also use muscular force to move.
Muscular force comes from living things.

2. Mechanical Force

We use different machines for doing many tasks. Muscular force is used for running some machines. Some machines are run by using electricity or fuel. Machines like the latter are called 'automatic machines', because a mechanical force is used here. For example, sewing machine, electric pump, washing machine, mixer, etc. Make a list of other such machines.

The force applied by means of a machine is called mechanical force.

Teacher's Note

A tractor in the field, a mixer in the kitchen, and a washing machine at home all use mechanical force. These machines make our work easier and faster.

Exam Trick

Remember: Mechanical = Machine. Machines use mechanical force. The tractor on the farm uses mechanical force to plough the soil.

Points to Remember

Machines use mechanical force to do work.
Electric pumps, tractors, and mixers use mechanical force.
Mechanical force can be very strong.
Machines run on electricity or fuel.
Mechanical force makes our life easier.

3. Gravitational Force

If an object is thrown upward by applying force, it reaches a certain height and comes down again. Why is this so?

Why do fruits on trees fall to the ground?

The earth pulls all the objects towards itself.

The force applied by the earth to pull objects towards itself is called gravitational force.

In the Past

Sir Isaac Newton discovered gravitation in the 17th century. The earth's gravitational force acts in a direction opposite to that of an object moving upwards. Hence, the speed of that object goes on decreasing till in the end it becomes zero. Then the object starts falling down instead of going up any further. While falling, its speed goes on increasing all the time due to gravitational force.

Teacher's Note

When you throw a ball up, it always comes down. This is because the earth pulls it down. This pulling force is called gravity, just like how your parents pull you towards them.

Exam Trick

Remember: Gravity = Pull of earth. Everything falls down because of gravity. An apple falls from the tree because of gravity.

Points to Remember

Gravitational force is the pull of the earth.
All objects fall to the ground because of gravity.
We need gravity to stay on the ground.
Fruits fall from trees because of gravity.
The earth pulls everything towards itself.

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