# How to Calculate a Change in Potential Energy

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Calculating the potential energy (PE) of a falling object is a fairly simple process involving only a few numbers and a bit of arithmetic. To figure out the change in potential energy, you do the calculation twice: once for the starting position, once for the final position, then you subtract the second energy result from the first.

1. ## Measure Initial Values

2. Measure the initial height and mass of the object. Record your values.

3. ## Calculate Initial PE

4. Calculate your object's initial potential energy using the following equation:

\text{PE}=\text{mass}\times g\times\text{height}

Use the height and mass you measured along with 9.8 m/s2 as the constant for gravity. The result will be your initial potential energy.

5. ## Measure Final Values

6. Determine the object's final height and mass. Record your values.

7. ## Calculate Final PE

8. Compute the object's final potential energy. Use the same equation as before while still using 9.8m/s2 as the constant for gravity. But, this time use your object's final height and mass. This number will be your final potential energy.

9. ## Calculate the Difference

10. Use the following equation to determine change in potential energy:

\text{change in PE}={final PE}-{initial PE}

The final number is your change in potential energy.

#### Things You'll Need

• Measuring stick
• Scale
• Calculator