Question

What is the magnitude of the torque about the point where the beam is bolted into place?

Answer 1

ANSWER:  The torque of the  beam is mgl/2.

Hi, since you didn´t put the whole problem I will solve your questions with this one.

A 2.90 m-long, 390. kg steel beam extends horizontally from the point

where it has been bolted to the framework of a new building under

construction. A 71.0 kg construction worker stands at the far end of

the beam. What is the magnitude of the torque about the point where

the beam is bolted into place?

STEP-BY-STEP EXPLANATION:

The sum of the torque is T1+T2, and the person is standing at the

edge of the beam. I do know the torque of the person standing at the

edge, which is 2.90 m * 71.0 kg * 9.8 m/s2  = 2.02 x 103 N-m.

Your  steel beam, assuming that it is uniform in mass, should have its

downward force exactly in the middle. Think of the steel beam as a

point particle, and all the mass is focused at its center. The product of

its weight and one-half its length will give you its torque. And the

person is standing at the edge at that distance, there is another

downward force there. Then sum up all the torques.

The torque of the  beam is mgl/2.