Potential energy is the amount of energy stored in an object before it is released. Gravitational potential energy is due to the fact that gravity is constantly pushing objects toward the Earth. Thus, when any object is held in the air it possesses potential energy because of the constant force of gravity. Therefore, we can calculate a change in potential energy by determining the initial amount of potential energy stored by the object and then subtracting the amount of potential energy at the end of the object's path.
Measure the initial height and mass of the object. Record your values.
Calculate your object's initial potential energy using the following equation: potential energy (PE) = mass * gravity * 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.
Determine the object's final height and mass. Record your values.
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.
Use the following equation to determine change in potential energy: Change in PE = Final PE – Initial PE. The final number is your change in potential energy.
Do not round your values. Be exact with your measurements. In some cases, even the smallest miscalculation may give you the wrong answer.
Remember to keep your units constant. Do not measure your initial height in feet and then measure your final height in meters. This will not give you the correct answer.