Conservation of energy

Work

the transfer of energy that occurs when a force is applied to an object, causing it to move in the direction of the force.

W = Fdcos0

Gravitational Potential Energy

Energy stored in an object due to its height in a gravitational field.

Eg = mgh

Power

The rate at which work is done or energy is transferred

Uses Watts (W)

P = w/t

Work-Energy Theorem

The net work done on an object equals the change in its kinetic energy

Wnet = KE

Energy

Ability to do work

Efficiency

Efficiency shows how much of the input energy is put to productive use and how much is wasted (often as heat, sound, or other forms of energy).

Using energy: Efficiency = Useful output/total output

Using power: Efficiency = Total power energy/input energy

Total = useful + waste

Conservation of Mechanical energy

Total Energy Before = Total energy after

(Energy is not made or destroyed)

Closed vs Open System

Open system: Energy and matter can freely enter

Closed system: Only energy can enter

Energy can enter both

Example of energy transfer

“Riding a bike”

Chemical energy (from eating food) → Mechanical energy (pedaling the pedals with legs)