Page 86 - Science class 4

10 Work, Force and Energy

l Force and its Types
l Types of Forces Gravity, Friction
Inside l Work and Machines
Inside
the
the
Chapter l Lever, Pulley, Wheel and Axle Inclined Plane, Screws, Wedge.
Chapter
l Energy and its Sources

l Sun. Wind, Water

FORCE

In our daily life, we lift, pull or push things.
A pull or a push acting on an object is called

force.
We can move objects, or change their

shapes, by applying force.

The picture below shows Rakshita and her
friends enjoying their summer holidays.
The children are playing football and

skipping the rope.
Circle the children who are applying a force.

Types of Forces

Force may cause an object to stop or start
moving, to change its position or direction,

or to increase or decrease its speed.

In nature, there are two types of forces

that are acting all the time : gravity and
friction.

Gravity
Gravity
Gravity
We see many examples of the force of gravity around us. The force that pulls
an object towards the centre of the Earth is called gravity or gravitational