The amount of work done in a certain amount of time?

The amount of work done in a certain amount of time is the power.

Power is measured in watts, and is defined as joules per second. Work is a mechanical form of energy. Dimensionally, it is Force*Distance. Typical units are ft-lb or watt-seconds. Power is the rate of work, dimensionally Force*Distance/Time. Typical units could be ft-lb/hour, or watt.