Kinetic energy and potential energy are two fundamental forms of mechanical energy in physics.
Kinetic Energy
Kinetic energy is the energy that an object possesses due to its motion. It depends on the mass of the object and its velocity. The formula for kinetic energy (KE) is:
\[ KE = \frac{1}{2} mv^2 \]
where:
- \( m \) is the mass of the object (in kilograms),
- \( v \) is the velocity of the object (in meters per second).
This means that the faster an object moves or the more massive it is, the more kinetic energy it will have.
Potential Energy
Potential energy is the energy that an object possesses due to its position or configuration. There are various types of potential energy, but the most commonly referenced type is gravitational potential energy, which depends on an object's height above a reference point. The formula for gravitational potential energy (PE) is:
\[ PE = mgh \]
where:
- \( m \) is the mass of the object (in kilograms),
- \( g \) is the acceleration due to gravity (approximately \( 9.81 , \text{m/s}^2 \) near the Earth's surface),
- \( h \) is the height of the object above a reference point (in meters).
Relationship Between Kinetic and Potential Energy
Kinetic and potential energy often convert into each other in systems. For example, in a pendulum, when it is at its highest point, it has maximum potential energy and minimal kinetic energy. As it swings down, potential energy converts into kinetic energy, reaching maximum kinetic energy and minimal potential energy at the lowest point. The total mechanical energy in a closed system remains constant, assuming no external work is done on the system. This principle is a key concept in the conservation of energy.