(i)[5]
Show that the magnitude of the particles’ acceleration is $2.5\,\text{m s}^{-2}$ and find the tension in the string.
(ii)[2]
Find the speed at which $B$ reaches the floor.
(iii)[4]
Find the speed at which $A$ reaches the pulley.
Mathematics 9709 · AS & A Level · Newton's laws of motion
Newton's laws of motion — practice question
Particle $A$ has mass $1.26\,\text{kg}$ and particle $B$ has mass $0.9\,\text{kg}$. They are joined to the two ends of a light inextensible string. This string runs over a small smooth pulley $P$, which is fixed at the edge of a rough horizontal table. $A$ is initially held at rest $0.48\,\text{m}$ from $P$, while $B$ hangs vertically below $P$, with its height $0.45\,\text{m}$ above the floor (see diagram). The coefficient of friction between $A$ and the table is $\frac{2}{7}$. $A$ is released and the particles begin to move.