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

$A$ boy of mass $40 \, kg$ runs up a flight of $50$ steps,each $10 \, cm$ high,in $5 \, s$. Find: $(i)$ the work done by the boy,and $(ii)$ the power developed. $(g = 9.8 \, m s^{-2})$

$A$ light and a heavy object have the same momentum. Find the ratio of their kinetic energies. Which one has a larger kinetic energy?

$A$ body is moving with constant speed over a frictionless surface. What is the work done by the weight of the body?

An object of mass $10 \ kg$ is made to fall freely from a height of $10 \ m$. Complete the table:

Height of object $(m)$	$PE$ $(J)$	$KE$ $(J)$	Mechanical Energy $(J)$
$10$	...	...	...
$8$	...	...	...
$5$	...	...	...
Just above ground	...	...	...

Hence,state the law of conservation of energy.

An iron sphere of mass $30 \, kg$ has the same diameter as an aluminium sphere whose mass is $10.5 \, kg$. The spheres are dropped simultaneously from a cliff. When they are $10 \, m$ from the ground,they have the same: