Mathematics 9709 · AS & A Level · Newton's laws of motion
Newton's laws of motion — practice question
A block $B$, with mass $2\,\text{kg}$, rests on a rough inclined plane that makes an angle of $30^\circ$ with the horizontal. A light rope, which is at $20^\circ$ above the line of greatest slope, is fixed to $B$. The rope tension is $T\,\text{N}$. A friction force of $F\,\text{N}$ acts on $B$ (see diagram). The coefficient of friction between $B$ and the plane is $\mu$.
(a(i))[3]
You are told that $F = 5$ and that $B$ accelerates up the plane at $1.2\,\text{m s}^{-2}$. Determine $T$.
(a(ii))[3]
Determine the value of $\mu$.
(b)[3]
Now suppose instead that $\mu = 0.8$ and $T = 15$. Decide whether $B$ will move up the plane.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Resolve the forces parallel to the plane” …