Magnetic Fields Unit Review

1. Short Answer: The space launch goal is to get our spacecraft traveling 100 m/s. Using iterative testing, what would be the next step you would take to try to meet that objective (goal)?

• Move the spacecraft to 2.5 cm.
• Make the magnet on the spacecraft weaker.
• Increase the weight of the spacecraft.

2. Mrs. Caraway is experimenting with a magnetic roller coaster ride. In one ride, there are two identical roller coaster cars (orange and green) that start on opposite sides of a large magnet. Mrs. Caraway wants to get the largest percentage increase in potential energy by moving one car one space to the RIGHT. Which movement should she make?

• Mrs. Caraway should move the orange car to B.
• Mrs. Caraway should not move the cars to the right.
• Mrs. Caraway should move the green car to D.
• Mrs. Caraway should keep the cars in the position they were originally in.

3. The above choice (in the previous question) will result in the highest amount of potential energy because...

• Moving anything results in potential energy (pe). PE is the energy of movement.
• Moving against the magnetic force gives us the greatest change in Potential Energy.
• All result in the same change in Potential Energy. Caraway moved each car one space.
• The closer you are to the magnetic force, the stronger the potentail energy.

4. Mrs. Caraway puts two magnetic toy trains very close to each other on a track. What will happen next, and why?

• The trains will not move because the magnets are not touching.
• The trains will move together because the magnets are attracting.
• The trains will repel because of the potential energy in the system will be converted.
• The trains will move away from each other because the magnets are not touching.

5. Based on the magnetic field line diagrams, what will happen next with these two sets of magnets.

• In both sets the magnets will repel.
• In both sets the magnets will attract.
• The magnets in Set 1 will repel, and the magnets in Set 2 will attract.
• The magnets in Set 1 will attract, and in Set 2 they will repel.

6. Andy moves a magnet toy train away from a magnet that can’t move. What happens to the potential energy in the system of magnets after the train is moved? The potential energy...

• increases because the train moves against the magnetic force.
• decreases because the train moves against the magnetic force.
• increases because the train moves with the magnetic force.
• does not change because the magnets in the system do not change.

7. A spaceship is traveling through space. Suddenly, its speed increases. What can you say about the kinetic energy of the spaceship?

• The kinetic energy decreases as it is converted into speed.
• There must have been more kinetic energy because the speed increased.
• The kinetic energy was converted into thermal energy.
• There is no way to know what happened to the kinetic energy.

8. What happens to the energy in a system of magnets when the magnetic force causes two magnets to move?

• The potential energy in the system increases.
• The kinetic energy in the system decreases.
• Some kinetic energy converts into potential energy.
• Some potential energy converts into kinetic energy.

9. Mikayla has two identical vehicles (purple and pink) that start on opposite sides of a center magnet that cannot move. She moves both vehicles one space further from the center magnet. How did the potential energy of the two vehicles change? The potential energy...

• for the two vehicles decreased.
• for the two vehicles increased.
• for the pink car increased, but the purple car decreased.
• for the pink car decreased, but the purple car increased

10. If I have two repelling magnets, and I push them closer together, what happens to the potential energy in the system?

• The potential energy decreases because you are pushing with the force.
• The potential energy increases because you are pushing with the force.
• The potential energy increases becuase you are pushing against the force.
• The potential energy decreases becuase you are pushing against the force.