A 1400 kg wrecking ball hangs from a 20-m-long cable. The ball is pulled back until the cable makes an angle of 23.0 ∘ with the vertical. Part A By how much has the gravitational potential energy of the ball changed?

21813.46 J

Explanation:

The Potential energy stored at the time it is hanging freely is mgl.

the potential energy stored at the time when it makes a angle 23 degree from the vertical is mglCos 23

Change in gravitational potential energy

U = mgl = mgl cos 23

U = mgl (1 - cos23)

U = 1400 x 9.8 x 20 (1 - Cos 23)

U = 21813.46 J