Formative Assessment

A person is walking on a horizontal road and carrying a briefcase. The work done by the person on the briefcase is _____.

Name five devices and the energy conversion that takes place in the devices.

A $2 \mathrm{kg}$ ball is dropped from a height of $10 \mathrm{m}$. Find its kinetic energy just before hitting the ground. [Take $\mathrm{g} =10 \mathrm{m} {\mathrm{s}}^{-2}$]

A $2 \mathrm{kg}$ ball is dropped from a height of $10 \mathrm{m}$. Find its kinetic energy just before hitting the ground. Find the velocity of the ball just before hitting the ground.[Take $\mathrm{g}= 10 \mathrm{m} {\mathrm{s}}^{-2}$].

A body is thrown up with a kinetic energy of $100 \mathrm{J}$. Find the potential energy at the topmost point.

A body is thrown up with a kinetic energy of $100 \mathrm{J}$. Find the height attained by the body in this case if the mass of the body is $1 \mathrm{kg}$. (Take $g = 10 \mathrm{m}/{\mathrm{s}}^2$)

If a man lifts a load up with the help of a rope such that it raises a load of mass $50 \mathrm{kg}$ to a height of $20 \mathrm{m}$ in $100$ seconds. Find the power of man. (Take $\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-1}$)

Find the time required to spent energy of$100 \mathrm{J}$ by a machine of power$10 \mathrm{W}$?