In a "worst-case" design scenario, a 2000 kg k g elevator with broken cables is falling at 4. 00 m/s 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 m as it does so. spring coefficient is 10. 6 kn/m k n / m. during the motion a safety clamp applies a constant 17000-n n frictional force to the elevator.