# Homework Help: Holding up a sign

1. Mar 24, 2015

### PierceJ

1. The problem statement, all variables and given/known data
You are holding a sign as shown below. The sign (including the horizontal bar it hangs from) has a mass of 1.80 kg and is 36.5 cm wide. The sign is hanging from a 1.30 m tall, 4.16 kg vertical post. The sign is symmetric with a uniform mass distribution as implied by the drawing.

What external force (+ if up, - if down) and torque (+ for CCW, - for CW) do you have to apply with your hand to keep the sign in static equilibrium? [Use g = 9.80 m/s2 and ignore the width of the vertical post.]

2. Relevant equations
Torque = Fd = 0

3. The attempt at a solution
I'm not quite sure how to deal with the vertical stick.
Torque = F1d1 - F2d2 - Fd3 = 0
As far as the set up goes, this is all I've got and I don't think it is correct. I may not be visualizing this problem correctly.

2. Mar 24, 2015

### PhanthomJay

There is an external unknown vertical reaction force and an unknown torque at your hand. You should identify these as V and T, respectively. Now apply your equilibrium equations to solve for them. Although explain what F1 ,d1 ,etc. are.

3. Mar 25, 2015

### CWatters

How about starting with a free body diagram?