energy, work and power

energy

capacity to do work
SI unit: J (Joule)

types of energy
kinetic energy

energy of an object due to its motion

potential energy

stored energy in a system, due to position, shape, or state

electrical energy

energy of an electric charge due to its motion and position

light

form of electromagnetic wave that is visible to the eye
made up of oscillating electric and magnetic fields

thermal energy

energy stored in the body due to its thermal properties

nuclear energy

energy released during nuclear reaction

principles of conservation of energy

energy cannot be created or destroyed but can be converted from one form to another. total energy in an isolated system is constant

KE formula

1/2 m v^2
m = mass of object
v = velocity

GPE formula

mgh
m = mass of object
g = gravitational field strength
h = height

work done

work done by a constant force on an object is the product of the force and the distance moved by the object in the direction of the force

work done formula

f x s
f = force applied
s = distance moved by object in direction of the force

conservation of energy 4 steps

power

rate of work done

power formula

work / time or energy / time
SI unit: W (Watt)

efficiency

useful energy output / useful energy input x100%
useful power output / useful power input x 100%