How much work should be done on an object of $120 \, kg$ to increase its speed from $25 \, m s^{-1}$ to $40 \, m s^{-1}$ (in $, J$)?

When a coil spring is compressed,the work is done on the spring. The elastic potential energy:

State whether the following statement is true or false:
Work done by centripetal force is zero.

The speed of a particle is doubled,its kinetic energy:

$(a)$ Define the term 'average power'.
$(b)$ When a player hits a football,it moves along a curved path and then falls to the ground. Calculate the work done by the force of gravity on the football.
$(c)$ Two friends,Ram and Shyam,each having a mass of $40 \, kg$,go for rock climbing. Ram climbs to a height of $3 \, m$ in $10 \, s$ and Shyam covers the same height in $12 \, s$. Is the work done by Ram and Shyam equal or not? Compare the power of Ram and Shyam.

$A$ light and a heavy body have the same momentum. Which one will have greater kinetic energy?