Two charges are separated by a distance of r. The distance between the charges is tripled to 3r. If the original force between the charges was 45 N, what is the new force between the charges?

Hint: This is a CHANGE problem, follow the change problem steps:

Write the original equation
Replace any variable which isn’t changing with a (1)
Replace any variable which is changing with the factor it changes by, like (x 2) or (x ¼)
Do algebra to solve for the change you want
Multiply the change by the original value to get the new value (if needed)
Responses

5 N
5 N

135 N
135 N

15 N
15 N

405 N