How Do You Calculate Alpha for a Lever's Force and Moment?

[bobbarkernar]

Homework Statement

a 2.9 lb force P is appplied to the lever which controls the auger of a snowblower. determine the value of alpha knowing that the moment of P about A is counterclockwise and has a magnitude of 17 lb*in

Homework Equations

The Attempt at a Solution

i thought i could do it using moment= F*d
so 17=2.9 tan^-1(alpha)*4.8 see picture attatched
i did it this way and i was a couple of decimas off so if someone can point me in the right direction thank you

 

[teknodude]

M = F*d only applies if your moment arm is perpendicular to the line of action of the force.

This is a 2-D problem so you have 3 equations that you can write down. Once that's done, you can see how to solve for the angle.