Force exerted by 2 supports on the plank

[pech0706]

Homework Statement

Suppose a crate of mass 7.5 kg is placed on the plank in the figure below, at a distance of 3.9m from the left end. Find the forces exerted by the 2 supports on the plank.

Homework Equations

Torque=radius*force

The Attempt at a Solution

I've used the tourque equation to get an answer around 66 for the force of the first support (the farthest to the left). I'm getting an answer in the 400's for the second support. I know the answers are supposed to be 130 N and 60 N. So, do I need to be using a different equation?

 

[gneill]

A 7.5kg mass only represents a weight of about 73.5N. So something's missing in your problem statement, perhaps the mass of the plank?