A sphere of mass 78 kg is attached to one end of a rope as shown in the figure below. It is found that the rope does an amount of work

W = 3550 J
in pulling the sphere upward through a distance 4.6 m. Find the work done by the force of gravity on the sphere.

My work

W= -78 * 9.8 * 4.6 = -3516.24

Answer: -3520