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, compressing 2.00 m as it does so. During the motion a safety clamp applies a constant 17000-N frictional force to the elevator. What is the speed of the elevator after it has moved downward 1.00 m from the point where it first contacts a spring?

Answer 1

Ok so this problem has me really confused. So i set up the equation that
E(final)-E(initial)=Work(by non cons forces). So I set it up as
[PE(spring) + KE(final) of elevator +PE(final) of elevator] - [KE(initial) of elevator +PE(initial) of elevator]=17000

Answer 2

This must be wrong because I get a speed that is 7.2m/s. Which is more than it is at first.