Mathematics 9709 · AS & A Level · Newton's laws of motion
Newton's laws of motion — practice question
Particles $A$ and $B$, with masses $0.9\,\text{kg}$ and $0.6\,\text{kg}$ respectively, are joined by the ends of a light inextensible string. The string passes over a fixed smooth pulley. The system is let go from rest while the string is taut, the two straight sections are vertical, and the particles are at the same level above the horizontal floor. In the motion that follows, $B$ does not reach the pulley.
(i)[4]
Determine the acceleration of $A$ and the tension in the string during the interval before $A$ reaches the floor.
(ii)[4]
After $A$ has landed on the floor, $B$ continues to travel vertically upwards for a further $0.3\,\text{s}$. Find the height of the particles above the floor at the instant when they began to move.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Newton’s second law applied to either mass” …