(i)[3]
Show that the tension in the string equals $10\,\text{N}$.
(ii)[2]
Calculate the modulus of elasticity for the string.
(iii)[3]
Find the magnitude and direction of the force exerted on the lamina by the surface at $A$.
Mathematics 9709 · AS & A Level · Probability
Probability — practice question
A uniform triangular lamina has weight $19\,\text{N}$, with $AB = 0.22\,\text{m}$ and $AC = BC = 0.61\,\text{m}$. Its plane is vertical. Point $A$ is in contact with a rough horizontal plane, and $AB$ is vertical. The lamina is kept in equilibrium by a light elastic string of natural length $0.7\,\text{m}$, which passes over a small smooth peg $P$ and is fixed to $B$ and $C$. The part of the string joined to $B$ is horizontal, whereas the part joined to $C$ is vertical (see diagram).