AP Physics 1: Chapter 8: Rotational Equilibrium and Dynamics

For the wheel-and-axle system shown above, which of the following expresses the condition required for the system to be in static equilibrium?

A uniform rigid bar of weight W is supported in a horizontal orientation as shown above by a rope that makes a 30° angle with the horizontal. The force exerted on the bar at point O, where it is pivoted, is best represented by a vector whose direction is which of the following?

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• 
• 
• 

A system of two wheels fixed to each other is free to rotate about a frictionless axis through the common center of the wheels and perpendicular to the page. Four forces are exerted tangentially to the rims of the wheels, as shown above. The magnitude of the net torque on the system about the axis is:

• FR

• 2FR

• 5FR

• 14FR

• mg

• T-mgR

• mgR-T

• zero

• zero