Answer:
-26.35 J
Step-by-step explanation:
a) Since the ball is hanging on a 1.35m string from the ceiling, the balls height with respect to the ceiling would be -1.35m. It's negative because the ball is below the ceiling.
Let g = 9.81m/s2
Gravitational potential energy of the ball relative to the ceiling would be the product of its mass and its height relative to the ceiling and its gravitational constant g
E = mgh = 1.99 * 9.81 * (-1.35) = -26.35 J