Question

The rope of a swing is 3.1 m long. Calculate the angle from the vertical at which a 77-kg man must begin to swing in order to have the same kinetic energy at the bottom as a 1430-kg car moving at 1.05 m/s (2.35 mi/hr).

Answer 1

KE=1/2 1430*1.05^2 solve that.

swing: PE at top=Ke at bottom
mgh=above KE
solve for h

Now, the angle.

draw the diagram. I see
cosTheta=(L-h)/L L is the swing rope length.
solve for Theta