NCERT Solutions for Chapter: Work and Energy, Exercise 2: Short Answer Questions

Can any object have mechanical energy even if its momentum is zero? Explain.

Can any object have momentum even if its mechanical energy is zero? Explain.

The power of a motor pump is $2 \mathrm{kW}$. How much water (in kilogram) per minute the pump can raise to a height of $10 \mathrm{m}?$

(Given $g=10 \mathrm{m} {\mathrm{s}}^{-2}$, only write the magnitude of the answer in the given box, no need to write the unit.)

The weight of a person on a planet $A$ is about half that on the earth. He can jump up to $0.4 \mathrm{m}$  height on the surface of the earth. How high he can jump on the planet $A?$

The velocity of a body moving in a straight line is increased by applying a constant force $F$, for some distance in the direction of the motion. Prove that the increase in the kinetic energy of the body is equal to the work done by the force on the body.

Is it possible that an object is in the state of accelerated motion due to external force acting on it, but no work is being done by the force. Explain it with an example.

A ball is dropped from a height of $10 \mathrm{m}$. If the energy of the ball reduces by $40\%$ after striking the ground, how much high can the ball bounce back? $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$

If an electric iron of $1200 \mathrm{W}$ is used for $30$ minutes every day, find electric energy consumed in the month of April.