Item RG122002: As two oppositely charge particles move closer together, the potential energy decreases, and the kinetic energy increases.
A negatively charged particle, Particle A, is traveling at a constant speed in a straight line. It gets close to a positively charged particle, Particle B, as shown below.
The two particles are attracted to each other and begin to move toward each other. Which of the following statements correctly describes any changes in the potential energy and kinetic energy of the system of particles as they move toward each other?
- The potential energy and kinetic energy both increase.
- The potential energy stays the same, and the kinetic energy increases.
- The potential energy decreases, and the kinetic energy increases.
- The potential energy and kinetic energy both stay the same.
- Distribution of Responses

- Scale Score for Item Difficulty
(200[Easy]-800[Difficult]) - 514
- Students Responding Correctly
Group | Correct | Total | Percent |
---|---|---|---|
Overall | 551 | 1495 | 37% |
Grades | |||
4–5 | N/A | N/A | N/A |
6–8 | 280 | 810 | 35% |
9–12 | 271 | 685 | 40% |
Gender | |||
Male | 268 | 720 | 37% |
Female | 274 | 753 | 36% |
Primary Language | |||
English | 510 | 1350 | 38% |
Other | 28 | 110 | 25% |
- Disciplinary Core Ideas
- PS3.A Motion energy is properly called kinetic energy; it is proportional to the mass of the moving object and grows with the square of its speed.
PS3.C When two objects interacting through a field change relative position, the energy stored in the field is changed. - NRC Framework
- Energy is also stored in the electric fields between charged particles and the magnetic fields between magnets, and it changes when these objects are moved relative to one another.