Energy Conversion and Conservation
Transcript Energy Conversion and Conservation
ENERGY CONVERSION AND
Review - Work
Work is done when a force acts on an
object in the direction the object moves.
Work = Force x Distance
The joule (J) is the SI unit of work.
Review - Power
Power is the rate of doing work.
Power = Work / Time
P = W/t
The SI unit of power is the watt (W)
Review - Energy
Work causes a change in the energy
of a system.
The two main types of energy are:
Review – Kinetic Energy
Kinetic energy depends on motion
and is measured in joules (J).
KE = ½ mv2
v = velocity
Review – Potential Energy
Gravitational Potential Energy
depends on height and is measured in
PE = mgh
h = height
g = acceleration due to gravity 9.8m/s2
Energy can be converted from one
form to another.
The process of changing energy from
one form to another is energy
EX: Rubbing hands – kinetic energy to
Conservation of Energy
When energy changes from one form
to another, the total energy remains
The law of conservation of energy
states that energy cannot be created
The gravitational potential energy of an
object is converted to the kinetic energy of
motion as the object falls.
EX: sky diving
The kinetic energy of motion is converted to
gravitational potential energy when an
object is gaining height.
EX: pole vaulting
Energy Conversion in a
Your beginning energy must equal your
ending energy. This allows us to say that:
(KE + PE)beginning = (KE + PE)end
Which means you can set kinetic energy
equal to potential energy.