Mathematics 9709 · AS & A Level · Representation of data
Representation of data — practice question
A particle $P$ with mass $0.2\,\text{kg}$ is connected to one end of a light elastic string whose natural length is $0.75\,\text{m}$ and modulus of elasticity is $21\,\text{N}$. The opposite end of the string is fixed at a point $A$, which lies $0.8\,\text{m}$ vertically above a smooth horizontal surface. $P$ is at rest in equilibrium on the surface.
(i)[2]
Find the magnitude of the force that the surface exerts on $P$.
(ii)[3]
$P$ is then projected horizontally along the surface with speed $3\,\text{m s}^{-1}$. Calculate the extension of the string at the instant when $P$ leaves the surface.
(iii)[3]
Hence find the speed of $P$ at the instant when it leaves the surface.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Writes equation $0.2g = R + 21\times\frac{0.05}{0.75}$” …