Mathematics 9709 · AS & A Level · Newton's laws of motion
Newton's laws of motion — practice question
A light inextensible string passes over a fixed smooth pulley and joins particles of masses $0.8\text{ kg}$ and $0.2\text{ kg}$. The system starts from rest, with each particle $0.5\text{ m}$ above a horizontal floor (see diagram). During the motion that follows, the $0.2\text{ kg}$ particle does not reach the pulley.
(a)[4]
Show that the magnitude of the acceleration of the particles is $6\text{ m s}^{-2}$, and determine the tension in the string.
(b)[3]
When the $0.8\text{ kg}$ particle reaches the floor it comes to rest. Determine the greatest height of the $0.2\text{ kg}$ particle above the floor.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Use Newton’s second law for a particle or for the system, for example $0.8g - T = 0.8a$, $T - 0.2g = 0.2a$” …