Mathematics 9709 · AS & A Level · Representation of data
Representation of data — practice question
$ABCD$ shows a cross-section through the centre of mass of a uniform rectangular block weighing $260\,\text{N}$. The lengths $AB$ and $BC$ are $1.5\,\text{m}$ and $0.8\,\text{m}$ respectively. The block is in equilibrium with point $D$ resting on a rough horizontal floor. A light rope holds the block in equilibrium, being attached to point $A$ on the block and point $E$ on the floor. The points $E$, $A$ and $B$ lie on one straight line that is inclined at $30^\circ$ to the horizontal (see diagram).
(i)[5]
By taking moments about $D$, demonstrate that the tension in the rope is $146\,\text{N}$, correct to 3 significant figures.
(ii)[4]
Assuming the block is in limiting equilibrium, calculate the coefficient of friction between the block and the floor.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Moments about $D$ used: $0.8T = 260\times DG \times \cos\theta$” …