What Is Energy

Energy is one of those concepts that sounds simple but gets complicated quickly. Basically, energy is the ability to do work. And work, in physics, is force applied over a distance.

Here's the beautiful part about energy: it doesn't disappear. It just changes forms. This is called the conservation of energy, and it's one of the most important ideas in all of physics.

Kinetic Energy: The Energy of Motion

Anything moving has kinetic energy. The formula is KE = ½mv² - mass times velocity squared. Notice the velocity is squared? That means doubling your speed quadruples your kinetic energy. That's why car crashes at high speeds are so much more dangerous.

Potential Energy: Stored Energy

Potential energy is energy stored waiting to be used. The most common type is gravitational potential energy - stuff up high has energy because gravity could make it fall.

Think about a roller coaster at the top of a hill. It has lots of potential energy. As it goes down, that potential energy becomes kinetic energy. The total stays the same - just conversions happening.