What Is the Net Torque on a Uniform Beam?

[Hotsuma]

Homework Statement

Determine the net torque on the 4.5-m-long uniform beam shown in the figure:
http://session.masteringphysics.com/problemAsset/1057865/3/GIANCOLI.ch10.p030.jpg"

A) Calculate about point C, the center of mass (CM)

B)Calculate about point P at one end.

Homework Equations

$\tau=F*\theta$

The Attempt at a Solution

In this case I have the answers for the values with the same figure, so I know the summation of forces along this pole must be equal to 8.5 N. From there I multiply the length of my bar to get 38 Nm, which is correct. However, I don't know how to get this from the figure. From there, I have no idea how to get the torque around point p.

 

[Delphi51]

The formula is not correct. It should be the component of force perpendicular to the rod times the distance from the point.

For the uppermost force, it would be
Torque = 56*sin(30)*4.5/2

 

[Hotsuma]

Solved! Thanks so much! Will you help me on this one?

https://www.physicsforums.com/showthread.php?p=2103356