## Physics Old Free Response

SHS AP QUIZ 8 KEY 1976 B1 The two guide rails for the elevator shown above each exert a constant friction force of 100 newtons on the elevator car when the elevator car is moving upward with an acceleration of 2 meters per second squared. The pulley has negligible friction and mass. Assume g = 10 m/sec2. (a) On the diagram below, draw and label all forces acting on the elevator car. Identify the source of each force. (b) Calculate the tension in the cable lifting the 400-kilogram elevator car during an upward acceleration of 2 m/sec2. (Assume g 10 m/sec2.) (c) Calculate the mass M the counterweight must have to raise the elevator car with an acceleration of 2 m/sec2.