posted by Mike aloe .
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?
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?