The combined mass of the wheelbarrow and its load is 90 kg. A worker pushes the wheelbarrow and load up a plank of length $2.0\,\text{m}$ onto a platform. The platform is $0.60\,\text{m}$ above the ground. The worker applies a force of $290\,\text{N}$ to the wheelbarrow in the same direction as its motion.
(a(i))[2]
Take the gravitational field strength $g$ as $10\,\text{N kg}^{-1}$. Calculate the gravitational potential energy gained by the wheelbarrow and its load.
(a(ii))[2]
The worker moves the wheelbarrow $2.0\,\text{m}$ along the plank. Calculate the work done on the wheelbarrow by the worker.
(a(iii))[1]
Suggest one reason why the value in (a)(ii) is different from the value in (a)(i).
(b(i))[1]
State what efficiency means.
(b(ii))[1]
Suggest one reason why lifting the load onto the platform by this method is so inefficient.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Use the relation g.p.e. = mgh” …