Original Project
Force and Motion
Item FM090002: A wagon that is being pulled with a constant force can move faster than the person pulling it if the force of the pull is greater than the force of friction on the wagon.
A girl is pulling a wagon on level ground. She is running at constant speed and pulling on the wagon with constant force.
Could the wagon move faster than the girl is running?
- Yes, but only if she wasn’t running fast.
- Yes, but only if she pulled harder and harder.
- Yes, but only if the force of her pull on the wagon was greater than the force of friction on the wagon.
- No, because if she was pulling with constant force, the wagon would have to move at constant speed.
- Distribution of Responses
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 445 | 1779 | 25% |
| Grades | |||
| 6–8 | 261 | 1117 | 23% |
| 9–12 | 181 | 654 | 28% |
| Gender | |||
| Male | 173 | 824 | 21% |
| Female | 260 | 909 | 29% |
| Primary Language | |||
| English | 390 | 1567 | 25% |
| Other | 48 | 177 | 27% |
- Disciplinary Core Ideas
- PS2.A The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.
PS2.A Newton's second law accurately predicts changes in the motion of macroscopic objects.