Work, Energy and Power — MCQ Practice

A block of mass $2\text{ kg}$ is pulled by a force of $10\text{ N}$ along a horizontal surface. If the block moves a distance of $5\text{ m}$ and the force makes an angle of $60^\circ$ with the horizontal, what is the work done by the pulling force?

A $0.5\text{ kg}$ ball is dropped from a height of $20\text{ m}$. What is its kinetic energy just before it hits the ground? (Assume $g = 10\text{ m/s}^2$ and neglect air resistance)

A pump is required to lift $600\text{ kg}$ of water per minute from a well $20\text{ m}$ deep and eject it with a speed of $10\text{ m/s}$. What is the power required by the pump? (Take $g = 10\text{ m/s}^2$)

A particle moves along the x-axis from $x=0$ to $x=5\text{ m}$ under the influence of a force $F = (7 - 2x + 3x^2)\text{ N}$. What is the work done by the force?

A body of mass $m$ is accelerated uniformly from rest to a speed $v$ in time $t$. The instantaneous power delivered to the body as a function of time $t'$ (where $0 \le t' \le t$) is proportional to:

A $10\text{ kg}$ block is released from rest at the top of a $30^\circ$ incline. The block slides $2\text{ m}$ down the incline and has a speed of $2\text{ m/s}$ at the bottom. What is the work done by friction? (Take $g = 10\text{ m/s}^2$)

Which of the following statements is INCORRECT regarding conservative forces?