How does a motor that runs on alternating current move?
Is the only difference between an AC and DC motor that one using alternating current and one uses direct current?
Sorry, I'm an engineer-in-training 
Here's a link to get you started.
http://www.johnsonelectric.com/en/resources-for-engineers/motors/basics-of-motors/ac-motors-theory.html
TraciAG:
How does a motor that runs on alternating current move?Is the only difference between an AC and DC motor that one using alternating current and one uses direct current?
Sorry, I'm an engineer-in-training
There are literally dozens of kinds of motor, so we'll assume you mean an induction
motor, being the commonest AC motor type.
The stator creates a rotating magnetic field as the current(s) alternate. This induces
current in the rotor (which is basically a set of shorted one-turn coils), and this
current acts as an electromagnet that interacts with the stator field to push the rotor
round. They are cheap and reliable (no brushes).
Induction motors have massive turn-on current spikes, so the larger ones usually have
a soft-start mechanism.
The other widespread ac motor type is the universal motor, which will work from
ac or dc, as only the relative phase of the armature and field coil current determines
the direction of rotation. They have brushes are are commonly used in power tools as
they can spin a lot faster than an induction motor which is fixed by mains frequency.