Q7 - This problem has three parts. I will list the questions for all three parts and any additional info below in "Description".

Question

A 500 lb steel beam is lifted up by a crane to a height of 100 ft and is held there.

Part a) How much work is being done to hold the beam in place?

Part b) How much work was done by the crane to lift the beam?

Part c) How much work would the crane have to do on the beam to raise it from 100 ft to 200 ft?

Answer 1

Imperial units for work are ft-lbs.

a) No work is being done as its energy (Potential or Kinetic) is not changing.

b) Force ⋅ distance = Work

c) Force ⋅ Δ distance = Work. Δ distance = (200 ft - 100 ft)