energy ch. 5. energy i. energy – the ability to do work (or cause change) most energy can be...
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Energy
I. Energy – the ability to do work (or cause change)
Most energy can be classified into 2 general categories:
Energy
1. Potential energy (PE) – stored energy or energy of position
PE = mghmass (kg)
9.8 m/s2 height (m)
Energy Types
Type KE
vs
PE
Description Examples
MechanicalEnergy
Both Energy associated withmotion and positionof everyday things
Speeding train,Bouncing ball,
Sprinting athletes
Thermal(Heat)Energy
KEEnergy is the motion ofparticles (faster = more
heat)
Candles, electricheaters
Energy Types
Type KE
vs
PE
Description Examples
ChemicalEnergy
PEStored in chemical
bonds in compounds(broken bonds – PE
Increases)
Gasoline,food, battery
RadiantEnergy
KEEnergy of
electromagneticwaves, including light
Solar energyX-rays
Radio waves
Energy Types
Type KE
vs
PE
Description Examples
SoundEnergy
KE Energy that movesthrough substances
(compression waves)
Music,Pencil hits floor,
etc
ElectricalEnergy KE
Movement of electricalcharges
Electricity inwires,
lightning
Energy Types
Type KE
vs
PE
Description Examples
NuclearEnergy
PE Energy that is stored in the nucleus (holds p+ &
neutrons together)
Sun (fusion), Powerplants
(fission)
Law of Conservation of Energy
A. Energy may change forms but it cannot be created or destroyed
B. If energy is conserved, then PE = KE ( is “change in”)
C. Conservation of Mechanical Energy:(KE + PE)beginning = (KE + PE)end
D. Energy flowchart shows how energy changes form.
Law of Conservation of Energy
a. The life of Stretchy the Rubber Band:
Stretchy is pulled – KE PE
Stretchy is released – PE KE
Stretchy is broken –
KE heat & sound
Energy ProblemsTo demonstrate a cheerleading stunt, Miss
Rokosik has to lift Miss Kalousek over her head (to a height of 2 m). Miss Kalousek has a mass of 50 kg. What is the potential energy of Miss Kalousek?
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