Physics Guide
Sign in
Back to Problems
F = ma (Final Problems)
Rotation
FMA-2020B-21 · 2020B F = ma (AAPT)

2020 F = ma Exam B — Question 21

A person stands on the seat of a swing and squats down, so that the distance between their center of mass (CM) and the swing’s pivot is `. As the swing gets to the lowest point, the speed of their CM is v. At this moment, they quickly stand up, and thus decrease the distance from their CM to the swing’s pivot to `0 . Immediately after they finish standing up, their CM speed is v 0 . Which of the following statements is correct? You may neglect friction, the change in moment of inertia of the person about their CM, and the time taken to stand up.
Source: Question 21, 2020 F = ma Exam B, © 2020 American Association of Physics Teachers (AAPT) and the U.S. Physics Team. Adapted by PhysicsTrainer: reformatted into a separate question and answer choices for online multiple-choice practice; any shared setup from nearby questions is repeated here. Not affiliated with or endorsed by AAPT or the U.S. Physics Team.