Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A girl riding a sledge begins at the top of a slope that is 100 m long and inclined at an angle of 20^\circ to the horizontal, with a speed of $5\text{ m s}^{-1}$. The sledge moves straight down the slope.
(i)[3]
Assuming there is no resistance to the sledge’s motion, calculate the speed of the sledge at the bottom of the slope.
(ii)[3]
It is now stated that the sledge has a resistance to motion so that the total work done against the resistance is $8500\text{ J}$, and the speed of the sledge at the bottom of the slope is $21\text{ m s}^{-1}$. Find the combined mass of the girl and the sledge.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Loss of gravitational potential energy $= mg \times 100\sin20$” …