Question

A 1200 wrecking ball hangs from a 20 -long cable. The ball is pulled back until the cable makes an angle of 30.0 with the vertical.By how much has the gravitational potential energy of the ball changed?

Answer 1

draw the figure. From the swing point, the initial point was 20 below, at the new point, it is 20cos30 below. What is the difference?