Free AP Physics C lesson

Torque & Cross Product

This AP Physics C: Mechanics lesson is designed for AP Physics C self-study. It includes 3 video lessons, 6 practice questions, and an estimated completion time of 20 minutes.

Video lessons

  1. Torque

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  2. Torque and Cross Product (part 2)

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  3. Torque and Cross Product (part 3)

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Practice covered

  1. Which of the following factors does NOT affect the magnitude of torque?
  2. A force of 8 N is applied to a wrench at a distance of 0.25 m from the bolt. The force makes an angle of 30^circ with the wrench handle. Calculate the magnitude of the torque (in Ncdotm).
  3. What is the effective lever arm (also called the moment arm)?
  4. A uniform meter stick of mass 0.5 kg is held horizontally at one end and released. At the instant of release, what is the magnitude of the torque due to gravity about the pivot point?
  5. A meter stick pivoted at one end is released from a horizontal position. At what position during its fall is the torque due to gravity equal to zero?
  6. Two forces act on a wheel with two different radii fused together. A force of 10 N pulls tangentially on the outer radius of 0.3 m, and another force of 10 N pulls tangentially on the inner radius of 0.1 m in the same rotational direction. What is the magnitude of the net torque (in Ncdotm)?
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