Goal: Perceiving the presence of forces from changes in position.
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
(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.