Question

In a "worst-case" design scenario, a 2000 kg elevator with broken cables is falling at 4.00 m/s when it first contacts a cushioning spring at the bottom of the shaft. The spring is supposed to stop the elevator eventually. The stiffness of the spring is 10.3 kN/m. During the motion a safety clamp applies a constant 16.9 kN frictional force to the elevator.

a) What is the speed of the elevator after it has moved downward 1.20 m from the point where it first contacts the spring ignoring friction?

b) What is the speed of the elevator after it has moved downward 1.20 m from the point where it first contacts the spring including friction?

c) When the elevator is 1.20 m below point where it first contacts the spring, what is the magnitude of its acceleration including friction?

Answer 1