Conservation of Mechanical Energy

CONCEPT

Mechanical Energy is the energy associated with motion. Mechanical Energy is divided into potential and kinetic energy.

Potential energy: the energy stored within an object.

For example, a stretched bow of an archer.

The formula for potential energy is
mass x gravitational acceleration x height

Kinetic energy: the energy possessed by the object because of its motion or because of its velocity.

For example, a person running.

The formula for kinetic energy is 0.5 x mass x velocity2





EQUATIONS + SOLUTION

Kinetic Energy
Determine the Kinetic Energy of a rabbit hopping with velocity of 2 m/s and 12 kg mass.
KE= 0.5 x m x v2
KE= 0.5 x 12 kg x 22
KE= 24 Joules

Potential Energy
Determine the Potential Energy of a chandelier hanging from the ceiling with a mass of 4 kg, hanging 5 m high and 12 m/s2 for the gravitational acceleration.
PE= m x g x h
PE= 4 kg x 12 m/s2 x 5m
PE= 240 Joules


CONSERVATION OF ENERGY

- It is the transformation from one form of energy into another.
- Instruments or objects which help the transformation are called converters.
- Example: a lamp turned on changes electrical energy into light and thermal energy.