A construction crew needs to hoist a load of mass 87 kg by means of a rope passing through a pulley.
They are going to lift the load from rest on the ground to a height of 18 m, and must reach the end
point with 2.0 m/s of velocity. (a) Calculate the work done by the crew on the load if they accelerate
it uniformly for the whole distance. (b) Repeat the calculation for the case where the acceleration is
carried out for the first 5 m and the load is lifted with constant velocity for the rest of the trajectory.