Magnetic Fields End-of-Unit Assessment

The letters N and S show the magnetic poles. Ramon puts two magnetic toy trains very close to each other on a track. What will happen next, and why?

• (a) The trains will move closer to each other because the magnetic force will pull the trains together.

• (b) The trains will not move because the magnets are not touching.

• (c) The trains will move away from each other because the magnetic force will push the trains apart.

• (d) The trains will move away from each other because the magnets are not touching.

The letters N and S show the magnetic poles. In a computer simulation, Jeffrey moves a magnet (Magnet 2) toward another magnet (Magnet 1) that cannot move. What happens to the potential energy in the system of magnets?

• The potential energy does not change because the magnets in the system do not change.

• The potential energy increases because Magnet 2 moves against the magnetic force.

• The potential energy decreases because Magnet 2 moves against the magnetic force.

• The potential energy decreases because Magnet 2 moves in the same direction as the magnetic force.

The letters N and S show the magnetic poles. Cherise sets identical magnetic carts on two tracks. At the end of each track is a large magnet that cannot move. Cherise can move the carts one space to the left or one space to the right. Which movement will result in the largest increase in potential energy?

• Moving the cart on Track 1 one space to the right (→).

• Moving the cart on Track 2 one space to the left (←).

• Moving the cart on Track 2 one space to the right (→).

• All these movements will result in the same change in potential energy because they each move a cart the same distance.

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

• The magnets in Set 1 will repel, and the magnets in Set 2 will attract.

• The magnets in Set 1 will attract, and the magnets in Set 2 will repel.

• The magnets in Set 1 will not move, and the magnets in Set 2 will attract.

• In both sets, the magnets will attract.

The letters N and S show the magnetic poles. Eli is holding two magnets close to each other. What will happen when he lets go?

• The magnets will not move because the magnets are not touching.

• The magnets will move closer to each other because the magnetic force will pull the magnets together.

• The magnets will move away from each other because the magnets are not touching.

• The magnets will move away from each other because the magnetic force will push the magnets apart.

The letters N and S show the magnetic poles. Abdul moves a magnetic toy train away from a magnet that cannot move. What happens to the potential energy in the system of magnets during the movement?

• The potential energy decreases because the train moves in the same direction as the magnetic force.

• The potential energy decreases because the train moves against the magnetic force.

• The potential energy increases because the train moves against the magnetic force.

• The potential energy does not change because the magnets in the system do not change.

The letters N and S show the magnetic poles. An engineer is investigating potential energy with two identical magnetic roller coaster cars on different sides of a center magnet that cannot move. To test her ideas, the engineer will move one car one space. Which movement will result in the largest increase in potential energy?

• Moving Car 1 one space toward the center magnet.

• Moving Car 2 one space away from the center magnet.

• Moving Car 2 one space toward the center magnet.

• All these movements will result in the same change in potential energy because they each move a roller coaster car the same distance.

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

• The kinetic energy increases as its speed increases.

• The kinetic energy decreases as it is converted into speed.

• The kinetic energy remains the same because speed and kinetic energy are not related.

• There is no way to know what happens to the kinetic energy.

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 changes into potential energy.

• Some potential energy changes into kinetic energy.

The letters N and S show the magnetic poles. Julia puts two magnetic toy trains very close to each other on a track. What will happen next, and why?

• A) The trains will move closer to each other because the magnetic force will pull the trains together.

• B) The trains will move away from each other because the magnetic force will push the trains apart.

• C) The trains will move away from each other because the magnets are not touching.

• D) The trains will not move because the magnets are not touching.