Potential energy (U) is energy dealing with systems of objects that exert forces on one another. Potential energy of an object can change as a reference frame changes. For example, an apple 10 feet off the ground on a shelf would have a different value of potential energy if you considered the potential energy from the shelf or from the ground.
When dealing with objects rising or falling, the change in potential energy is equal to the negative of work done. This equation works for gravitational forces or spring forces.
In addition, when dealing with forces, we must differentiate between conservative and nonconservative forces. A conservative force does work on an object that is equal to the negative of the work done in the opposite direction. Some examples of conservative forces are gravity and spring forces. An interesting application of conservative forces is that conservative forces are independent of path. This means that you could go from point A to point B in an infinite number of ways and still do the same amount of work. So, when a conservative force is acting on an object on a closed path (a path where you end where you start), the net fore is equal to zero.
However, nonconservative forces do not preserve energy within a system. Frictional forces and drag forces are a few examples of nonconservative forces. For example, if you were to kick a ball on the ground, eventually it would stop moving due to friction. Therefore, energy is lost in the system to thermal energy, and thus friction is a nonconservative force. Thermal energy cannot be changed back into kinetic energy, whereas gravity (a conservative force) can change kinetic energy into potential energy and vice versa with no energy loss.
Gravitational potential energy is equal to the product of mass, acceleration due to gravity, and the height above the ground (U=mgy). Elastic potential energy is equal to half of the product of the spring constant and the distance squared (U=1/2kx2). Also, the change in potential energy is equal to the integral of a force function from one point to another point.Potential energy (U) is energy dealing with systems of objects that exert forces on one another. Potential energy of an object can change as a reference frame changes. For example, an apple 10 feet off the ground on a shelf would have a different value of potential energy if you considered the potential energy from the shelf or from the ground.
When dealing with objects rising or falling, the change in potential energy is equal to the negative of work done. This equation works for gravitational forces or spring forces.
In addition, when dealing with forces, we must differentiate between conservative and nonconservative forces. A conservative force does work on an object that is equal to the negative of the work done in the opposite direction. Some examples of conservative forces are gravity and spring forces. An interesting application of conservative forces is that conservative forces are independent of path. This means that you could go from point A to point B in an infinite number of ways and still do the same amount of work. So, when a conservative force is acting on an object on a closed path (a path where you end where you start), the net fore is equal to zero.
However, nonconservative forces do not preserve energy within a system. Frictional forces and drag forces are a few examples of nonconservative forces. For example, if you were to kick a ball on the ground, eventually it would stop moving due to friction. Therefore, energy is lost in the system to thermal energy, and thus friction is a nonconservative force. Thermal energy cannot be changed back into kinetic energy, whereas gravity (a conservative force) can change kinetic energy into potential energy and vice versa with no energy loss.
Gravitational potential energy is equal to the product of mass, acceleration due to gravity, and the height above the ground (U=mgy). Elastic potential energy is equal to half of the product of the spring constant and the distance squared (U=1/2kx2). Also, the change in potential energy is equal to the integral of a force function from one point to another point.
