A particle $P$ with mass $0.6\text{ kg}$ is connected to one end of a light elastic string whose natural length is $0.8\text{ m}$ and whose modulus of elasticity is $24\text{ N}$. The opposite end of the string is fixed at point $A$, and $P$ hangs in equilibrium.
(i)[2]
Calculate how much the string extends.
(ii)[4]
From the equilibrium position, $P$ is projected vertically downwards with speed $4.5\text{ m s}^{-1}$. Find $AP$ when $P$ is moving at $3.5\text{ m s}^{-1}$ and lies below the equilibrium position.
(iii)[3]
Calculate $P$'s speed when it is $0.5\text{ m}$ above the equilibrium position.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply Newton’s restitution or impulse equation, for example $24e/0.8 = 0.2g$” …