1. The problem statement, all variables and given/known data . Consider the energy of a 100 kg rock. a) What is the gravitational potential energy (PE) of the rock that is 5 m above the ground? b) The rock falls to the ground. What is its PE? c) What is the change in PE of the rock? d) What is the change in the kinetic energy of the rock? 2. Relevant equations MGH 3. The attempt at a solution a) 100*9.8 m/s2*5 = 4900 J b) 0J c) Change in PE = 4900 J d) Change in KE = ½ * 100kg * (9.9 m/s)2 = 4900 J Can anyone look at my answers?