Things You'll Need:
- Calculator
-
Step 1
Understand what kinetic energy is. Energy is what enables things to happen or, as physicists put it, for work to be done. Energy comes in many forms. Heat, electricity, and light are forms of energy. Kinetic energy is what we also call energy of motion. It can not only be transferred to other objects, it can be transformed into other forms of energy. For example, when the falling water in a hydroelectric plant turns an electric generator, the kinetic energy of the moving water is being transformed into electrical energy.
-
Step 2
Know how kinetic energy is measured. Scientists usually measure kinetic energy in Newtons (named for Isaac Newton). A Newton is the energy required to change the velocity of 1 kilogram of mass by 1 meter per second. You can use other measures as well. For example, sometimes engineers use English measure where the unit is the foot-pound (the energy needed to change the velocity of 1 pound by 1 foot per second). You calculate theoretical kinetic energy the same way, but be sure to uses units of measure that are all in the same system.
-
Step 3
Find the mass of the object whose kinetic energy you want to calculate. You may need to look up the mass of a car or use a scale to weigh an object for a science experiment. Keep in mind that mass is not the same as weight. Weight is actually the force with which the Earth’s gravity pulls on an object. An object will weigh a bit less at the top of a mountain where the Earth’s gravity is slightly reduced, but the amount of mass (the material the object is composed of) is the same. For most everyday purposes the difference between weight and mass isn’t important. However, when you need to make precise calculations, you need to be sure you are measuring mass and not weight, or you will get the wrong answer.
-
Step 4
Measure the velocity of the object. To keep things simple, let’s assume you just want to calculate the theoretical kinetic energy of an object moving at a given speed, rather than going to the trouble of actually doing an experiment and measuring the velocity.
-
Step 5
Calculate the theoretical kinetic energy. The equation for calculating kinetic energy is K = 1/2M(v^2) where K is the kinetic energy, M is the mass, and V^2 is the square of the velocity. For example, if you want to calculate the K for a mass of 5 kilograms moving at 10 meters per second you multiply 5 kilograms times one-half times the square of 10 meters per second (the answer is 250 Newtons).
