A force can change the shape and size of an object.

Describe Galileo's experiment. What was the result of this experiment ?

A body moves with constant velocity of $20 \mathrm{m} {\mathrm{s}}^{-1}$. The mass of body is $2 \mathrm{kg}$. The unbalanced force acting on the body is _____ $\mathrm{N}$.

Fill in the blank with a suitable word from the bracket

Force that enables us to walk is called _____ (magnetism/friction).

A child bends his plastic measuring scale as shown in the diagram. Is he pushing or pulling the scale? What is the effect of the force on the scale?

Name the force used to pull a trolley.

Define Newton's first law and Inertia.

State Newton's first law of motion.

A force can change the direction of motion of an object.

Match the columns.

Think about the following real-life examples where force is applied. On the right side, the possible effects of force are given. Select and write the correct effect for each of the examples. 

Force applied	Effect of force
1. A girl is pushing a baby stroller.	The force causes a change in the shape.
2. A boy is hitting a ball with a bat.	Force stops the movement.
3. A girl is pressing a balloon.	Force starts movement in the object.
4. A girl is catching a ball.	The force causes a change in the path of the object.

What is friction? How is it a beneficial force?