Kelly carried a box weighing 10 N the 200 meters from his car to his new house.  George took the box from Kelly and carried it up the 3 meter tall flight of stairs.  Who did more work?


Sagot :

While moving box from car to house
W = F * d * cosine (90 degree)
= 10N * 200m * 0 
= 0Nm

While lifing 3m tall flight of stairs
W=F*d*cosine(0 degree)
= 10N * 3m
= 300 Nm

George did more work

I think George did more work because George moved the box to the same direction as the force that he applied. So he is applying an upward force to the box to keep it from falling down and moving to the box up the stairs and Kelly does move the box farther than George, but he isn´t doing any work before the force he applies to the box on a different direction than movement.


Hope this helps


Tobey