Original Project
Energy: Forms, Transformation, Transfer, and Conservation
Item NG090002: Assuming no energy transfer between a ball and the track it is moving in, the speed of the ball will be the same before and after rolling over a hill because the total amount of energy in the system does not change.
Imagine a ball on a track where no energy is transferred between the ball and the track or between the ball and the air around it. It is going fast enough at Position 1 so that it will go over a hill on the track and past Position 2. Position 1 and Position 2 are at the same height.
Will it be going faster, slower, or at the same speed at Position 2 compared to Position 1 and why? (Remember that no energy is transferred between the ball and the track or between the ball and the air around it.)
- Faster, because new energy in the form of motion energy (kinetic energy) was made when the ball went down the steep side of the hill
- Slower, because motion energy (kinetic energy) was used up when the ball went up the long side of the hill
- The same speed, because the amount of motion energy (kinetic energy) that the ball has remained the same the entire time it was moving along the track
- The same speed, because the total amount of energy in the system (ball and track) did not change as the ball moved along the track
- Distribution of Responses
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 428 | 3002 | 14% |
| Grades | |||
| 6–8 | 229 | 1903 | 12% |
| 9–12 | 195 | 1087 | 18% |
| Gender | |||
| Male | 238 | 1464 | 16% |
| Female | 181 | 1486 | 12% |
| Primary Language | |||
| English | 377 | 2709 | 14% |
| Other | 38 | 217 | 18% |