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AP® Physics C: Mechanics

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Moderate

Physical Pendulum Torque

APPHMC-LNSPY2

A non-uniform rod of length $l$ and total mass $m$ swings from a pivot point, $P$, as shown below. The Center of Mass (CoM) for the rod is located at $\frac { 2 }{ 3 } l$.

J. Krehbiel. Created for Albert.io. Copyright 2016. All rights reserved.

What is the magnitude of the torque on the rod when it is displaced by an angle of $\theta $ from the vertical?

A

$\frac { 2 }{ 3 } mg$

B

$\frac { 2 }{ 3 } mgl$

C

$ mgl$

D

$\frac { 2 }{ 3 } mgl\cos { \theta } $

E

$\frac { 2 }{ 3 } mgl\sin { \theta } $