Fig. 1.1 illustrates a painter standing on a wooden plank, positioned directly above the support on the right.
The plank measures 3.6 m in length, 0.35 m in width and 0.025 m in thickness.
The gravitational field strength $g$ is $10\,\text{N kg}^{-1}$ and the plank has a mass of 23 kg.
(a)[2]
Calculate the density of the wood that makes up the plank.
(b(i))[1]
Calculate the weight of the plank itself.
(b(ii))[2]
Calculate the plank’s moment about the support on the right-hand side.
(c)[1]
As the painter moves further to the right on the plank, it turns about the right-hand support. Explain why it rotates.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$\rho = m / V$, or a correct numerical substitution” …