PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two carts, A of mass 2 kg and B of mass 1 kg, are connected by a light spring and move together with a speed of 3 m s⁻¹ on a smooth horizontal track. Cart A then passes over a rough section that exerts a constant 4 N force opposite to the motion on it for 0.25 s, while cart B continues on the smooth track. After cart A leaves the rough section, determine the speed of the centre of mass of the two-cart system.