R P Goyal and S P Tripathi Solutions for Chapter: Work, Energy and Power, Exercise 4: EXERCISE -2(B)

How much work is needed to be done on a ball of mass $50 \mathrm{g}$ to give it s momentum of $500 \mathrm{g} \mathrm{cm} {\mathrm{s}}^{-1}$?

How much energy is gained by a box of mass $20 \mathrm{kg}$ when a man carrying the box waits for five minutes for a bus?

How much energy is gained by a box of mass $20 \mathrm{kg}$ when a man runs carrying the box with a speed of $3 \mathrm{m} {\mathrm{s}}^{-1}$ to catch the bus ?