Julie is holding a 5 kg book 1 m above the ground, bob is holding a 10 kg book 2 m above the ground and anna is holding a 7.5 kg book 1 m above the ground. all three students hold their book steady without moving for 5 minutes. rank from greatest to least the amount of work being done by each person during this 5 minute period. (use > to indicate one value is greater than another, use = to indicate they are the same.)