Answer:
150000 J
Step-by-step explanation:
Only the work that is used to lift the boxes up by 1.5 m is counted against gravity. The work that is used to move 10m to the dock is not.
This work done to lift up by 1.5m is the product of force lifted F = 100 000 N and the vertical distance in height h = 1.5m
W = F*h = 100000*1.5 = 150000 J