Liftmaster Formula I.

When I hit the button the motor makes noise but the belt doesn't move. The
door moves on the track freely when I lift it manually. Examining the belt
I see the rubber has separated near the motor and only the steel belts are
visible. There is maybe an inch or two of slack in the belt when I pull on
it. This belt seems to be the problem to my untrained eye. Is this
something I can fix on my own?