Question

5. A passenger of mass 85 kg is riding in an elevator while The scale only reads the normal force it exerts on the (Note that 1 b 0.453 kg 4.45 N) a) What standing on a platform scale. does the scale read in pounds (lb) when the elevator is not moving? elevator is moving upward with an acceleration of 3.5 m/s?? c) What does the scale read in pounds (b) when the elevator is same acceleration of 3.5 m/s?? A car with a mass of 800 kg traveling around a curve with a radius of 20 m at a syp 72 km/hr. The coefficient of friction between the road and the tires is zero. 6. a) At what angle should the curve be banked? b) What is the magnitude of the centripetal acceleration of the car t is the magnitude of the centripetal force required to produce this acce

Answer 1

5) when the elevator is not moving , scale reads

F = mg = 85*9.8 = 833 N = (833 / 4.45) = 187.2 lb

b) when it moves upwards with 3.5 m/s2

F = mg + ma = 85(9.8 + 3.5) = 1130.5 N = (1130.5/4.45) = 254.04 lb

c) when it moves downwards with acceleration 3.5 m/s2

F = mg - ma = = 85(9.8 - 3.5) = 535.5 N = (535.5/4.45) = 120.33 lb