# Kinetic Energy

There are several different kinds of energy. Energy can be stored or transferred from place to place or from object to object. One kind of energy that all moving things have is called **kinetic energy**. It is energy possessed by an object due to its motion or movement. The word *kinetic* comes from an Ancient Greek word *kinesis* which translates to *motion*. Very large objects, like planets, and very small ones, like atoms, all contain kinetic energy because they are in motion. The heavier a thing is, and the faster it moves, the more kinetic energy it has.

There are two types of kinetic energy: transitional and rotational. **Transitional kinetic energy** depends on the motion through space, and an example would be a baseball pitcher throwing a ball. The ball contains the kinetic energy contained from the pitcher throwing the ball.

On the other hand, **rotational kinetic energy** depends on an object's motion that is centered on an axis, like the Earth's rotation on its axis. If an object's speed and mass are known, the amount of kinetic energy it contains can be calculated.

**Joule** is the measurement unit used for kinetic energy, and another unit for determining energy is known as the **newton** and is measured through a newton-meter. The direction of a moving object does not matter when understanding kinetic energy. It can move horizontally, vertically, or diagonally. When the speed of an object doubles, the kinetic energy it has will increase four times. However, when the mass of the object doubles, the kinetic energy of the object also doubles.

Kinetic energy can also be transferred from one object to another. For example, when a baseball is thrown by the pitcher, and the bat hits the ball, the bat transfers its kinetic energy to the ball and the ball moves in a different direction, containing all the kinetic energy.

In another example, a roller coaster that is pulled in an uphill manner will gain potential kinetic energy. Once the coaster cars hit the top of the structure, it has the most potential kinetic energy. It begins moving down the other side of the hill and gains speed as well as kinetic energy. By the time the coaster cars hit the bottom, it has achieved most of its kinetic energy and is also at its point of least potential energy.

If an object is to gain or increase its kinetic energy, work must be done to the object, such as the pulling of the coaster cars of the bat hitting the ball. Most of the kinetic energy starts as a different type of energy, such as potential, and is then converted.

Finally, if two objects are moving at the same speed, the object with more mass will have more kinetic energy. For example, if a bike and car were moving at the same speed, the car will have greater kinetic energy. The car would cause more damage if it collided with something versus the bicycle.

Another example is a car traveling at 60 mph has four times the kinetic energy of an identical car traveling at 30 mph. The car traveling at 60 mph has the potential for four times more death and destruction in the event of a crash.

In summary, all energy can be stored or transferred from place to place or from object to object. All moving things have kinetic energy due to its motion or movement and are determined by its mass and speed.

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