PhysicsLAB: Coulomb's Law: Some Practice with Proportions

Refer to the following information for the next ten questions.

Two charges, a +5 µC charge and a -6 µC charge, are 2 meters apart.

1. What is the magnitude of the original electrostatic force between them?

2. Is it an attractive or repulsive force?

3. What conditions could alter the nature of the force; that is whether it is attractive or repulsive?

4. How would the original force change if the charges were moved twice as far apart?

5. How would the original force change if the charges were moved towards each other to a final distance which equals half of their original separation?

6. How would the original force change if the charges were each doubled in size?

7. How would the original force change if each of the charges were to be cut in half?

8. How would the original force change if the charges were each doubled in size as well being moved to a distance that is twice their original separation?

9. Which of the following combinations of changes, involving both a change in the magnitude of the charges as well as their separation, could produce a force that is 64 times stronger than the original force between them?

you could quadruple each charge and also move them to new positions which represent a distance that is only half of their original separation
you could cut each charge in half and also move them to new positions which represent a distance that is 16 times greater than their original separation
you could double one charge, quadruple the second charge and move them to new positions which represent a distance that is 8 times greater than their original separation
you could double each charge and also move them to new positions which represents a distance that is only one-fourth their original separation

10. Which of the following combinations of changes, involving both a change in the magnitude of the charges as well as their separation, could produce a force that is only 1/24^th of the original force between them?

you could double one charge, triple the second charge, and also separate them to a distance which is 12 times their original separation
you could cut one charge in half, cut the second one by one-third and also separate them to a distance which is twice their original separation
you could leave one charge unchanged, cut the other to 1/6th its original charge and also separate them at a distance which is twice their original separation
you could double one charge, triple the second charge, and also separate them to a distance which is half of their original separation