Kinetic: energy of movement (depends on mass and velocity)
Potential: energy of position - gravitational: depends on mass, height and acceleration due to gravity - elastic: depends on ability to be stretched or compressed - chemical: stored in bonds - electrical: associated with charge - nuclear: stored in the atomic nucleus - electromagnetic: waves ( light/rays/sound )
Energy is never created or destroyed – it is transformed from one form to another. (PE+KE) Beginning = (PE+KE) End
Often, kinetic energy will be transformed into thermal energy, via FRICTION. This is the reason we always LOSE efficiency when work is done!
m = mass (kg) v = velocity (m/s) KE = kinetic energy (Joules)
What is the kinetic energy of a 75-kg student running at a speed of 3 m/s?
m = mass (kg) g = acceleration due to gravity (9.8 m/s 2 ) h = height (m) PE = potential energy (Joules)
A mover carries a television with a mass of 62 kg a distance of 18 m up the stairs. How much potential energy does the TV have? PE = (62)(9.8)(18) = 10,937 J
If 2500-kg roller coaster car begins its descent from 500 m above the first hill, what is its kinetic energy at the bottom of that hill? PE = (2500)(9.8)(500) = 12,250,000 J = KE!