A 4.0-m-long, 500 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 70 kg construction worker stands at the far end of the beam. What is the magnitude of the torque (in N m) about the point where the beam is bolted in place?
I was searching the internet to the answer to this problem when I figured it out.
We find the Xcm for the beam and the worker, then find the torque due to gravity. If you place the construction worker on the very right, then
Xcm = [(70×4) + (500×2)]/575 = 2.23m
Tg = -(M)(g)(Xcm) = -(575)(9.8)(2.23) = 12.5 kNm
which is the answer in the back of the book.Source(s): Knight Chapter 12