Page 142 - Active Science 5 Ebook and Activity

E ffects of Force

Force makes an object move
Force is an activity which changes the motion of an object. It can
make a stationary object move. Also, it can increase the speed of
a moving object. But the force applied here should be in the same
direction of the moving object. For example, a cat hits a ball with its
paws and makes it roll. It is the force that makes the ball move.

Force stops a moving object.
The natural state of an object can be changed by force. A force can
either set a stationary object into motion or stop a moving object. A
force can deflect a moving object by changing its speed or direction
or both, if force is applied in the opposite direction. For example, a

goalkeeper stops the ball to avoid the goal.

Force can change the direction of a moving object.
A force applied at an angle to the direction of motion of an object

can change its direction. For example, a football player changes
the direction of a moving ball by hitting it with force in a different
direction.

Force can change the shape of an object.
Force can change the shape of an object. For example, a child is
playing with clay. He wants to make a house of clay. He will apply
force on the clay to make the wall of that house, the stairs, the
roof, etc. Therefore, the shape of clay will be changed every time
after applying force.

T ypes of Forces

There are various types of forces— gravitational, electrostatic, frictional and magnetic

forces are very common examples.

Gravitational Force

Gravitational force is a force which brings down everything towards the earth. If
we throw anything upwards, it always comes down because of the earth’s gravitational
force. When an object moves away from the earth, the gravitational force always works
in the opposite direction. The earth and the sun have more gravity than others bodies in
the solar system. Gravity helps the earth to stay at just the right distance from the sun.

The sun’s gravity also keeps the earth in orbit around it. All heavenly bodies exerts force
of gravity. The heavier the body, the greater is its gravity.

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