Question

7.32 A 4.70-m-long, 540 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 73.0 kg construction worker stands at the far end of the beam.

part A)

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

Express your answer to three significant figures and include the appropriate units.

Answer 1

The sum of the torque is T1+T2, and the person is s
tanding at the
edge of the beam. I do know the torque of the perso
n standing at the
edge, which is 4.70 m * 73.0 kg * 9.8 m/s²
= 3.362 x 10³
N-m. Your
steel beam, assuming that it is uniform in mass, sh
ould 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 it
s torque. And the
person is standing at the edge at that distance, th
ere is another
downward force there. Then sum up all the torques.
The torque of the
beam is mgl/2
Torque at bolted end = (540 x 9.81 x (4.7/2)) + (73 x 9.81 x 4.7) = 15768.58 Nm.