Enter the change in work and change in time of an object or system to calculate the total power of that system.

Power Formula

The following formulas are used to calculate power.

P (Power) = dW/dt, 
  • where W is work
  • and t is time.

To calculate Power, divide the change in work by the change in time.

Power (P) = (W2-W1)/(T2-T1)

Power (P) = (W2-W1)/(T2-T1)

  • where W1 is the initial work
  • W2 is the final work
  • T2 – T1 is the total time passed

Power can also be described as the rate of transferring heat, which is synonymous with work. The international standard unit for power is joules per second (J/s). Unlike velocity, force, and acceleration, Power is a scalar quantity and has no direction.

In terms of electricity, the output power of an electric motor is the product of the torque and the velocity, or in terms of light, it’s measured in watts.

How to calculate power

We will now take a look at an example of how to calculate power. For this example, we will be looking at an electric motor.

  1. First, we need to set up our experiment. We hook up the electric motor to a gauge that measures work overtime.
  2. Next, we run the motor for a certain amount of time. Let’s say we run it for 10 seconds and the change in work is 10 J.
  3. Finally, enter that information into the equation above. P= 10J/10s = 1W.
  4. Analyze and adjust your results.

What is Power?

Power is the derivative of work with respect to time. In other words, it’s an amount of work over a given amount of time.