Cracking the SAT Physics Subject Test

Using the equation for the electric field strength due to a single point charge, we
find that

6. If a charge q = −5.0 pC were placed at the midway point
   described in the previous example, describe the force it would feel.
   (“p” is the abbreviation for “pico-,” which means 10−12.)

Here’s How to Crack It

Since the field E at this location is known, the force felt by q is easy to calculate.