a) W = Force x distance
In this case, the force = mg
W = mg * d = (1.6)(9.8)(10-1.5) = 133.28J
b) ΔU = Ub - Ua , where b is in the person's hands
ΔU = mghf - mghi = mg (hf -hi) = (1.6)(9.8)(1.5-10) = -133.28
c) Utop = mgh = (1.6)(9.8)(10) = 156.8 J
d) Ubottom = mgh = (1.6)(9.8)(1.5) = 23.52 J
e) Work is still force x distance, so taking the answer from part a..133.28J...
f) W = - ΔU = - 133.28J ( change in potential energy is the same as if the ground still had PE = 0, only dependent on what the final and initial point are..in other words, the change in height is still the same)
g)156.8 J + 100 J = 256. 8 J ( add 100 J to the normal PE, when ground is 0)
h)23.52 J + 100 J = 123.52 J ( add 100J to normal PE, when ground is just 0 )