What if Anything is Wrong

1. What if Anything is Wrong Force between Electric Charges

2. Task Description Four charged objects will be shown in a simulation. The net force on object due to all of the other charged objects is shown with an arrow. When two of the objects are brought close to each other, the net force will be largely between the two charges. Observe the simulation and then answer the following questions about what if anything is wrong.

3. What, if anything, is wrong with the simulation? • There is nothing wrong • The force was in the wrong direction on one charge • The force was in the wrong direction on a pair of charges • The forces failed to obey Newton’s third law

4. Which pair of particles had a force inconsistent with the others? • There is nothing wrong • A and B • A and C • A and D • B and C • B and D • C and D

5. What was wrong with the force vectors? • There is nothing wrong • One of the force arrows pointed the wrong way • Both force arrows pointed the wrong way

6. Three students are having a conversation about the fact that the electrostatic force can be both attractive and repulsive and what this means about charge.

7. Student A: “The fact that the force is both repulsive and attractive means there are exactly two types of charge. After all, opposites attract and likes repel.”

8. Student B: “There are more than two types of charge. An uncharged aluminum can is attracted to a charged rod. So neutral is also a charge.”

9. Student C: “There could be more than two types of charge. You could have two groups of charges that repelled each other within a group, but attracted charges in the other group.”

10. With which student do you agree? • A • B • C • I don’t agree with any of them

11. Why did you agree with that student? • I know there are only two types of charge • Since neutral objects attract, they must be charged • Attraction and repulsion imply at least two types of charge. There could be more. • Some other reason • I didn’t agree with any of them