V K Sally and R Goel Solutions for Chapter: Work and Energy, Exercise 5: Practice Problems

A boy pushes a cart through a distance of $100 \mathrm{m}$ by applying a force of $50 \mathrm{N}$. How much work is done by the boy?

A locomotive exerts a force of $7500 \mathrm{N}$ and pulls a train through $1.5 \mathrm{km}$. How much work is done by the locomotive?

A water tank top of a building $25 \mathrm{m}$ high contains $100 \mathrm{k} \mathrm{g}$ of water. Calculate the potential energy stored in the water (Take the gravitational acceleration $\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}$).

A stone of mass $5 \mathrm{kg}$ is lying at the edge of the cliff $80 \mathrm{m}$ vertical height from the ground level. Calculate the potential energy of stone. (Take $(\mathrm{g}=9.8 \mathrm{m} {\mathrm{s}}^{-2})$ 

 A boy does a work of $4000 \text{J}$ in $2$ minutes. Calculate the power of the boy in kilowatts.

A machine does a work of $25 \text{KJ}$ in $3$ minutes and $20$ seconds. Calculate the power of the machine in kilowatts.