Question

A lift was initially at an intermediate postion z₁=10m. It was raised to a position z₂=100m, and then it had a free fall and hit a spring at the base (z₃=0m). The mass of the lift is 2500kg. Given gravity, g=9.81m/s2.

a) Potential energy at z₁ with respect to the base?

b) What is the work done to raise the elevator to mg (z₂-z₁)?

c) What is the potential energy at the highest postion relative to the base?

d) Just before hitting the base, what is the kinetic energy?

e) What is the total energy of the system (spring and the lift) when the elevator comes to rest?

Answer 1