A2L Item 033
- Description: Determine the presence of a horizontal force from a strobe diagram.
- Goal: Perceiving the presence of forces from changes in position.
- Source: UMPERG
- Keywords: Forces, Graphing, Mechanics
The question for students:
Below is shown a strobe diagram indicating the position of four objects at successive time intervals. The objects move from left to right.
During the intervals shown, which of the objects experience no net force in the horizontal direction?
- Object A only
- Object B only
- Object C only
- Object D only
- Objects A and B
- Objects B and C
- Objects A and C
- None of the above
- Cannot be determined
Commentary for teachers:
Answer
(8); Objects with no net horizontal force will move with constant velocity. The objects moving with constant velocity are B and D. This question helps to reinforce the idea that it is change in motion, not motion itself, that requires a force.