# Homework Help: Free body diagram

1. Apr 5, 2008

### dranseth

1. The problem statement, all variables and given/known data
When drawing a freebody diagram for just an elevator, not the people in it, what are all the forces that we have to consider? I just used Fg down and Ft up, but because it is accelerating up, I made Ft greater.

2. Apr 5, 2008

### slider142

Just because the elevator is moving up, doesn't mean it is always accelerating up. It may only accelerate when it first starts moving and right before it stops at your floor. Otherwise, it may be moving with uniform velocity upwards.

3. Apr 5, 2008

### dranseth

Well, in the question it stated that it was accelerating... So was I right to have only the two forces Ft and Fg with Ft bigger?

4. Apr 5, 2008

### slider142

In that case, your diagram is correct to have Ft greater in magnitude than Fg, since Ft + Fg = Fnet = ma and a must be non-zero, and I'm assuming the elevator is accelerating in the direction of Ft. ;)

Last edited: Apr 5, 2008