1. A conservative force
   1. does no work on objects
   2. must be linear
   3. has an associated potential energy
2. Which of these is NOT a conservative force?
   1. air resistance
   2. gravity
   3. spring force
3. A speck of dust is pulled forward by an electric force. After it has moved forward 1 meter, its electric potential energy has
   1. decreased
   2. not changed
   3. increased