Mathematics 9709 · AS & A Level · Forces and equilibrium
Forces and equilibrium — practice question
A $3\,\text{kg}$ block is stationary on a rough plane that is tilted at $60^\circ$ to the horizontal. A force of $15\,\text{N}$, applied up the line of greatest slope of the plane, is just enough to stop the block from sliding down the plane.
(i)[5]
Find the coefficient of friction between the block and the plane.
(ii)[2]
A force of $15\,\text{N}$ is now replaced with one of magnitude $X\,\text{N}$ acting up the line of greatest slope. Find the largest value of $X$ that keeps the block at rest.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Normal reaction obtained as $R = 3g \cos 60$” …