PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A block of mass M=3.0kg rests on a horizontal table. The coefficient of kinetic friction between the block and the table is μk=0.15, and the coefficient of static friction is μs=0.20. The block is attached to a hanging mass m=1.2kg by a light string that passes over a small, friction-less pulley at the edge of the table. The system is released from rest.
Use g=9.8ms−2.
(a) On your answer sheet, draw separate free-body diagrams for the block on the table and for the hanging mass. Label all forces with their type and indicate their directions.
(b) Determine the magnitude of the acceleration of the system after release.
(c) Calculate the magnitude of the tension in the string while the system is accelerating.
(d) The hanging mass is replaced by an adjustable mass holder. What minimum mass must be placed in the holder so that the system is just on the verge of moving but remains at rest? Assume the same coefficients of friction quoted above.