Page 114 - Viva ICSE Science 4 : E-book

• Force can change the shape and size of an object.

• Force can change the direction of a moving object.

Did You Know!

There are diff erent types of forces present in the nature. Non-living things cannot
move on their own. They
Let’s discuss about some of them.
need a push or a pull
to move.
Types of forces

Muscular force is the force that is applied by the muscles

of the human body, like arms or legs, to do work. Lifting
a school bag, kicking a football, pushing a door and
carrying things in hands are some activities in which we

use muscular force.

Gravitational force is the force that pulls down every object towards the centre of the
earth. For example, whenever we throw something in the air, it always falls down on

the ground. This happens because of earth’s gravity or gravitational force. This force is
responsible for keeping us bound to the earth. Plants, animals, buildings, monuments
and everything on the earth are held by gravity.

Sir Isaac Newton was the fi rst person who discovered the gravitational force.

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