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Question
The density of a rod gradually decreases from one end to the other. It is pivoted at an end so that it can move about a vertical axis though the pivot. A horizontal force F is applied on the free end in a direction perpendicular to the rod. The quantities, that do not depend on which end of the rod is pivoted, are ________________ .
Options
angular acceleration
angular velocity when the rod completes one rotation
angular momentum when the rod completes one rotation
torque of the applied force
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Solution
torque of the applied force
The torque of the applied force does not depend on the density of a rod. It depend on the distance between the pivot and the point where F is applied. So, it does not depend on which end of the rod is pivoted.
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⊗ represents a unit vector coming out of the page.
⊗ represents a unit vector going into the page.
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