AP® Physics C: Mechanics

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Net Torque on a Multi-Object System

APPHMC-GH1DWK

Nick Borowicz. Created for Albert.io. Copyright 2016. All rights reserved.

The L-shaped figure above, of total mass $M$, is made out of two bars of length $L$ and $2.5L$ and connected to a wall with a frictionless pivot at its joint, about which it is free to rotate. Two blocks of mass $3M$ and $M$ hang from the end of each segment from extremely light rigid bars of negligible mass, making $45^{\circ}$ angles with the vertical.

What is the magnitude of the net torque on this system about its axis of rotation?

A

$\cfrac{5}{4}MgL$

B

$\cfrac{3}{2}MgL$

C

$\cfrac{3\sqrt{2}}{2}MgL$

D

$\cfrac{2\sqrt{2}}{3}MgL$

E

$\cfrac{\sqrt{2}}{8}MgL$