PHYS 2211 Module 10.8

Work and Power for Rotational Motion

Recommended Reading

10.8 Work and Power for Rotational Motion

Learning Objectives

By the end of this section, you will be able to:

  • Use the work-energy theorem to analyze rotation to find the work done on a system when it is rotated about a fixed axis for a finite angular displacement
  • Solve for the angular velocity of a rotating rigid body using the work-energy theorem
  • Find the power delivered to a rotating rigid body given the applied torque and angular velocity
  • Summarize the rotational variables and equations and relate them to their translational counterparts


Consider how you would answer these questions. Then bring this to class for a group discussion.

A rope pulls on a spool with a constant force, causing it to rotate. As the spool rotates, the rope rolls off. (The distance r changes as the rope comes off the spool.) How much work is done during the first rotation of the spool?