Law of
Conservation of Energy:
·
Energy cannot be created or
destroyed.
In other words, the total amount of energy in the
universe is constant!
But
energy can change forms over and over.
Light bulbs change electricity
into heat and light.
Cars (engines) change chemical
energy into heat and kinetic energy.
People change chemical energy
into heat, kinetic energy, and sound.
Mechanical
Energy:
·
The total amount of potential and kinetic energy in a
system (KE + PE)
High PE Low KE
High
KE
High
KE
Friction:
Will the swing keep moving forever?
No! Friction slows it down by converting the KE into sound and heat. But the total amount of energy stays the same.
