Calculating Torque in a Hanging Rod System

[Joosh]

Hey, folks! So upon studying for my Physics final tomorrow, I came across this question on the practice exam, which I know the answer is D from the solution key. However, I'm not sure how to get that for the answer.

1. Homework Statement

Homework Equations

τ = r_A × F_net
L_A = L_{trans, A} + L_rot
L_trans = r_cm × P_tot
L_rot = r₁ × p₁ + r₂ × p₂ + ...

The Attempt at a Solution

I personally don't entirely know where to start. I'm going to guess this is a torque-related question, but I'm not sure if that's the right way to go at it.

 

[PhanthomJay]

The rod is at rest when the force F is applied. What can you say about what the sum of the torques about the hinge must be for bodies at rest? No need to get involved with momentum

 

[Joosh]

The net torque would equal zero.

 

[haruspex]

The net torque would equal zero.

So what are the torques? What equation do you get for a zero sum?

 

[Joosh]

Would it just be gravity and the force pushing the rod upwards?

 

[Joosh]

I asked one of the graduate teaching assistants about this and he was able to help me figure this out. I simply forgot that the center of mass is where gravity is pulling down on the rod.