Exam-style question
Try this first
When a rotating object is brought to rest by a resisting torque, the work done by the resisting torque is equal to which of the following?.
- A.The increase in the object's rotational kinetic energy.
- B.The decrease in the object's rotational kinetic energy.
- C.The sum of the object's kinetic and potential energies.
- D.Zero, because the object stops.
Model answer
What a good answer should say
- The decrease in the object's rotational kinetic energy.
Explanation
Why this works
The resisting torque does negative work equal to the loss of rotational kinetic energy, conserving energy by converting it into other forms such as heat.
Common mistake
No common mistake is linked to this question yet.