Short lesson on kinetic energy.

The Energy of Motion


Sam Rosander

When something moves, we say that it has "kinetic energy." Kinetic energy is the energy of motion.

How do we measure kinetic energy? Can you think of any way to measure motion?

Speed is one way to measure motion. Speed is a measure of how much how quickly someone or something covers a distance, but it is also important to know which direction they are travelling.

The word for speed in a specific direction is "velocity." Velocity is an important part of kinetic energy, but it is not the whole thing.

Besides velocity, what might give an object or person more energy? Are there any differences that you can think of which might be important between, say, a bowling ball and a soccer ball moving at the same velocity?

We say that everything has a "mass." Mass is a measure of how much "stuff" there is. Electrons have the smallest mass that we can measure.

Weight is the pull of gravity on an object or person. Since the weight of a basket ball is different on Earth than it is on the moon, need a different way to describe weight.

Now that you know what kinetic energy is, think about some specific examples. 

Kinetic energy is measured by the mass and velocity of an object. Something with lots of mass and a low velocity can have the same kinetic energy as something with little mass and a high velocity.

Individual and groups of atoms have kinetic energy. In chemical reactions, atoms are attracted to each other or push each other away. These reactions are how fireworks explode and fire burns. Between the different kinds of potential energies (like chemical potential and gravitational potential) and kinetic energy, we can say that everything has energy.

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