Work, Energy and Power
JUPEB Physics
12 Work, Energy and Power practice questions covering everything you need for JUPEB.
Drill Work, Energy and Power →Sample Work, Energy and Power questions
A boy pulls a load with a rope inclined at $60^\circ$ to the horizontal using a force of $100$ N. If the load moves $5$ m horizontally, find the work done.
A stone is released from rest at a height of $20$ m. Neglecting air resistance, find its speed just before it hits the ground. (Take $g = 10$ m s$^{-2}$.)
A pump raises $200$ kg of water per minute through a vertical height of $15$ m. Calculate the power of the pump. (Take $g = 10$ m s$^{-2}$.)
An electric motor takes in $2000$ W and delivers a useful output of $1500$ W. What is its efficiency?
A car of mass $1000$ kg travelling at $20$ m s$^{-1}$ is brought to rest by its brakes in a distance of $50$ m. Find the average braking force.
A spring of force constant $200$ N m$^{-1}$ is compressed by $10$ cm. Calculate the elastic potential energy stored.
A $2$ kW electric heater is used for $3$ hours. How much energy does it consume, in joules?
A force of $50$ N moves a crate $4$ m in the direction of the force. Calculate the work done.
Calculate the kinetic energy of a $2$ kg body moving at $3$ m s$^{-1}$.
A $5$ kg bag of rice is lifted onto a shelf $10$ m above the ground. Find the gain in potential energy. (Take $g = 10$ m s$^{-2}$.)
A machine does $600$ J of work in $20$ s. Find its power.
A body of mass $4$ kg falls freely from a height of $45$ m. Find its kinetic energy when it is $20$ m above the ground. (Take $g = 10$ m s$^{-2}$.)