Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A load with mass $160\,\text{kg}$ is lifted vertically upward from rest at a fixed point $O$ on the ground by means of a winding drum. When the load reaches point $A$, which is $20\,\text{m}$ above $O$, its speed is $1.25\,\text{m s}^{-1}$ (see diagram). Find, for the motion from $O$ to $A$,
(i)[1]
the increase in the potential energy of the load.
(ii)[2]
the increase in the kinetic energy of the load.
(iii)[3]
You are told that the work done against the resistance to motion from $O$ to $A$ is $20\,\text{kJ}$ and that the time taken for the load to move from $O$ to $A$ is $41.7\,\text{s}$. Find the power output of the winding drum.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “PE gain is $32000\,\text{J}$” …