Question

Problem 1: A ball of mass 7.00 kg is dropped from a building of 20 m height and hits the ground. Now, in lecture we mentioned there is no absolute value for the gravitational potential energy Ugrav of a mass m, but what matters is the difference in Ugrav with respect to a ZERO where Ugrav = 0 J. So Ugrav is relative! Based on this: a) Set y = 0 m to the ground. What is the change in the potential gravitational energy ΔUgrav of the ball? b) Now, set your y = 0 m at exactly half-way of the height of the building (10m). What is the change in the potential gravitational energy ΔUgrav of the ball? c) What is the work done by the gravitational force when the mass moves downwards and hits the ground?

Answer 1