Original Project
Force and Motion
A moving object will maintain the same speed and direction of motion unless a force acts on it.
Item FM089002: A sled 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 sled.
A boy is pulling a sled with a rope on level ground covered with snow. Assume he is running at constant speed and pulling on the rope with constant force.
Could the sled move faster than the boy is running?
- Yes, but only if he wasn’t running fast.
- Yes, but only if the force of the pull on the sled was greater than the force of friction on the sled.
- Yes, but only if he was pulling the sled downhill and gravity was helping make it go faster and faster.
- No, because if he was pulling with constant force, the sled would have to move at a constant speed.
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 1722 |
6–8 n = 1101 |
9–12 n = 620 |
Male n = 844 |
Female n = 854 |
English n = 1590 |
Other n = 97 |
||
| A. | Yes, but only if he wasn’t running fast. | 6% | 7% | 5% | 7% | 5% | 6% | 11% |
| B. | Yes, but only if the force of the pull on the sled was greater than the force of friction on the sled. | 23% | 22% | 24% | 21% | 24% | 22% | 28% |
| C. | Yes, but only if he was pulling the sled downhill and gravity was helping make it go faster and faster. | 36% | 35% | 38% | 34% | 37% | 36% | 31% |
| D. | No, because if he was pulling with constant force, the sled would have to move at a constant speed. | 36% | 37% | 33% | 38% | 33% | 36% | 30% |