Will a 1/3 horse power sump pump motor burn up at half power?

[EricH]

I think that you may want to talk to your local physics teacher. At the least, he can help you through some of the concepts and the math behind them.

I'll give a brief rundown of some of them.

Voltage: difference in electrical potential energy between two points.
Amperage or current: how fast that electrical energy can move.

Power (or energy): force*distance.
Work: power/time.
Torque: force * distance, usually referenced with regard to rotational motion. You'll want to know this eventually.

Gearboxes multiply and divide torque and rotational speed, which translates via wheels to linear power and linear speed.

BTW, you may want to look up some of John V-Neun's whitepapers. I think that those will help you with some of the math that is behind the design of a drivetrain, and quite possibly help you optimize the drive for the motors you have.