Mechanical Energy

Mr. Bombick7th Grade Science

Types of Energy?

Mechanical Energy DefinitionThe form of energy due to the relative position of interacting bodies (potential energy) or to their motion (kinetic energy). Mechanical energy may be in the form of either potential energy or kinetic energy or both.

Potential Energy (PE)The most common type of potential energy associated with mechanical energy is gravitational potential energy. Gravitational potential energy can be defined as follows:

Gravitational Potential Energy = weight (Newtons) X height (meters)

Other Types of Potential Energy?

Potential Energy (cont.)

Potential energy, gravitational or otherwise, has significance only when it changes—when it does work or transforms to energy of some other type.

Kinetic Energy (KE)Energy of motion is called kinetic energy (KE). The kinetic energy of an object depends on mass and speed.

Kinetic Energy = 1/2mass X speed2

KE = 1/2m X v2

Work-Energy TheoremThe work-energy theorem states that work equals the change in kinetic energy. The work refers to the net work done in the system.

Work = KE

Conservation of EnergyEnergy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes.

Conservation of EnergyRDX or PETN Example

Conversion of the potential energy of the explosive into other forms of energy.

What are some of the other forms of energy released after the explosion?

Internal Combustion Engine Example

Conversion of the potential energy of gasoline into other forms of energy

What are the other forms of energy produced?