Dhiren M Doshi Solutions for Chapter: Work and Energy, Exercise 4: Check Your Progress

What happens to the potential energy of a body if its mass is reduced to one-fourth?

What happens to the potential energy of a body if it is raised four times the original height?

What happens to the potential energy of a body if it is lowered to half of its original height?

What happens to the potential energy of a body if the body is taken from the poles to the equator?

A boy of mass $50 \mathrm{kg}$ climbs up a height of $100 \mathrm{m}$. Calculate the amount of work done by him. How much potential energy does he gain? (take $g=10 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{s}}^2$}\right.$)

A wheat bag has a mass of $200 \mathrm{kg}$. To what height should it be raised so that its potential energy may be $9800 \mathrm{J}$? (take $\mathrm{g}=9.8 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{s}}^2$}\right.$)

 $4900 \mathrm{J}$ of work done in lifting a body of $50 \mathrm{kg}$ mass. Calculate the height through which this body was raised. (take $\mathrm{g}=9.8 \mathrm{m}/{\mathrm{s}}^2$)

A boy of mass $50 \mathrm{kg}$ climbs $30$ steps of a staircase, each measuring $20 \mathrm{cm}$ in height. Calculate the potential energy gained by the boy. (take $\mathrm{g}=10 \mathrm{m}/{\mathrm{s}}^2$)