Three identical trolleys P (mass 2 kg), Q (mass 1.5 kg) and R (mass 2.5 kg) are…
PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Three identical trolleys P (mass 2 kg), Q (mass 1.5 kg) and R (mass 2.5 kg) are connected in a straight line by two light strings and rest on a horizontal track. The coefficient of kinetic friction between each trolley and the track is 0.10. A horizontal force F is applied to trolley P in the forward direction so that the entire system moves with an acceleration of 1.2ms−2.
(i) Calculate the magnitude of the force F.
(ii) Determine the tension in the string between P and Q and that between Q and R during the motion.
(iii) If the same force F were instead applied to trolley R (pulling it in the same direction), find again the tensions in the two strings while the system accelerates at 1.2ms−2.