What is Kinetic Energy?
Definition of Kinetic Energy
Kinetic energy as defined by the Merriam Webster online dictionary states, "energy associated with motion." But what does that mean exactly?
According to the Department of Physics and Astronomy at Georgia State University, "Kinetic energy is an expression of the fact that a moving object can do work on anything it hits; it quantifies the amount of work the object could do as a result of its motion."
In layman's terms, kinetic energy is the energy that an object has due to it being in motion. Or better, the energy created by the motion of an object.
Definition of a Joule
A Joule is defined as, "the SI unit of work or energy, equal to the work done by a force of one newton when its point of application moves one meter in the direction of the action of the force, equivalent to one 3600th of a watt-hour (www.merriam-webster.com)."
How is Kinetic Energy Measured
Kinetic energy is typically measured using the metric system, also known as the SI system (French for Systeme international d'unites).
Mass - measured in kilograms (kg)
Velocity - measured in meters per second (m/s)
Kinetic Energy - measured in Joules (J)
Kinetic Energy Equation
The standard equation for Kinetic Energy is:
Kinetic Energy = 1/2 mv2
Where m = Mass and v = Velocity
Examples of Kinetic Energy
To better understand kinetic energy, here are some examples of kinetic energy
- Raindrops falling from the sky
- A bowling ball rolling down the lane
- A rollercoaster going downhill
- A bird soaring through the air
- A cue ball striking other pool balls
Who Discovered Kinetic Energy?
Galilieo Galilei and Isaac Newton, typically, get the credit for discovering kinetic energy. However, Aristotle did contribute to some theories regarding mass and velocity. They were able to figure out how forces were related to each other through motion. Netwon explains kinetic energy through his "laws of motion".
Newton's Three Laws of Motion
- First Law of Motion (Law of Inertia)- an object in motion will stay in motion, or an object at rest will stay at rest, unless acted upon by a force
- Second Law of Motion - the acceleration of an object is dependent upon the net force acting upon the object and the mass of the object
- Third Law of Motion - for every action, there is an equal and opposite reaction