Force F applied on a body moves it through a distance S along F. The energy spent is :

1. F x S
2. F/S
3. FS²
4. F/S²

In which case will the potential energy decrease ?

1. Compressing a spring
2. Stretching a spring
3. Moving a body against gravitation
4. A bus descending down a steep hill

Assertion (A): If momentum of a body increases by 50%, its kinetic energy will increase by 125%.

Reason (R): Kinetic energy is proportional to the square of velocity.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true and R is not the correct explanation of A.
3. assertion is false but reason is true.
4. assertion is true but reason is false.

Assertion (A): A spring has potential energy in both cases whether it is compressed or stretched.

Reason (R): This is because work is done on the spring against the restoring force.

1. both A and R are true and R is the correct explanation of A
2. both A and R are false and R is not the correct explanation of A
3. assertion is false but reason is true
4. assertion is true but reason is false