The ability to do work

Work = Force x distance

Kinetic: energy of movement (depends onmass and velocity)

Potential: energy of position- gravitational: depends on mass, heightand acceleration due to gravity- elastic: depends on ability to bestretched 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 istransformed from one form to another.

(PE+KE)Beginning = (PE+KE)End

Often, kinetic energy will be transformed intothermal energy, via FRICTION.

This is the reason we always LOSE efficiencywhen work is done!

2

2

1mvKE

m = mass (kg)v = velocity (m/s)KE = kinetic energy (Joules)

What is the kinetic energy of a 75-kg studentrunning at a speed of 3 m/s?

J 338)3)(75(2

1 2 KE

mghPE

m = mass (kg)g = acceleration due to gravity (9.8 m/s2)h = height (m)PE = potential energy (Joules)

A mover carries a television with a mass of 62 kga distance of 18 m up the stairs. How muchpotential energy does the TV have?

PE = (62)(9.8)(18) = 10,937 J

If 2500-kg roller coaster car begins its descent from500 m above the first hill, what is its kinetic energy atthe bottom of that hill?

PE = (2500)(9.8)(500) = 12,250,000 J = KE!