question_answer

In the figure, the blocks A, B and C weigh 3 kg, 4 kg and 8 kg respectively. The coefficient of sliding friction between any two surfaces is 0.25. A is held at rest by a massless rigid rod fixed to the wall, while B and C are connected by a light flexible cord passing around a fixed frictionless pulley. Find the force P (in N) necessary to drag C along the horizontal surface to the left at a constant speed. Assume that the arrangement shown in the diagram, B on C and A on B is maintained all throughout.

Answer:

78.40