# Homework Help: Need help on rotational dynamics problem quick please

1. Dec 16, 2004

### Crazedkid

hi i need help understanding what to do with the information that was given in the problem if u could point mein the right direction i would greatly appreciate it. thank you

An invered "A" is suspended from the ceiling by 2 verticle ropes. Each leg of the "A" has a length of 2L and a weight of 120.0N. The horizontal crossbar has a negligable weight. Find the force that the crossbar applies to each leg.
Known:
W=120.0N per leg
l of legs= 2L
angle at top of "A" = 60Degrees
l of crossbar=L

2. Dec 16, 2004

### Parth Dave

I think the key idea here is that the system is in static equilibrium. That means that the net force and torque are zero. Can you take it from there?

3. Dec 17, 2004

### ultimatejester

Parth Dave is right. The system is at rest so the net force is 0. If that is not the case read below.

the formula is W=Fcosd

but what doesnt make sense is that you dont have the displacement. Are you sure it says 2L not 2m.

Last edited: Dec 17, 2004