Find out how much the object weighs. If there is any added weight to the object make sure to calculate it. For example, if you want to find the center of gravity for a car with two people in it, weigh the car alone, weigh each person separately and then add all of their weights together.
Measure the length of each object from one end to the other. If we use the example from Step 1, you measure the car first. Next, measure the people from their backs to their chests. This is because the car is flat on the ground. If the car rested on its back bumper, you would measure the entire length of the people. Find half of each length and write it down.
Start the math. Multiply each distance by the weight of that object. Multiply the length of the car by its weight and so on.
Add the answers of the multiplication together to get the total measurement. Add the weights together.
Divide the total from Step 4 by the total weight to calculate the center of gravity for the object.