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9. Problem 11.67E (HRW) A cylinder having a mass of 2.0 kg can rotate about its central axis through point O. Forces are applied as shown in the figure:
Also,
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We
have to find the magnitude and direction of the angular acceleration of the
cylinder. (During their rotation, the forces maintain their same angles
relative to the cylinder).|
Solution: Click For PDF Version Mass of the cylinder m is 2.0 kg and its radius
Torque on the cylinder by each force is its magnitude times its moment arm
and its direction is as determined by the cross-product rule. We will call the
torque in the anticlockwise direction about the central axis positive. From the
diagram we note that the angles between the forces and the line joining the
point O to their point of application are either
Rotational equation of motion relates angular acceleration
Therefore, the angular acceleration of the cylinder will be
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is 0.12 m. Rotational inertia of the cylinder about its central axis
Therefore, the net torque is
and
torque on a rigid body
