Download Chapter 15.1

Chapter 15.1
ž  Energy
is the ability to do work. Work and
energy are very closely related!
ž  Work is a transfer of energy.
ž  Work and energy are measured in joules (J).
Think about the work and
energy involved in doing
something as simple as
carrying your backpack!
ž  The
energy of motion.
ž  The kinetic energy of any moving object
depends upon its mass and speed.
KINETIC ENERGY FORMULA:
KE= ½ mv2
ž  mass
in kg
ž  Velocity in m/s
ž  KE in J (joules)
*Hint- Square your
velocity first,
multiply by your
mass, and then
multiply by .5
ž  A
.10 kg bird is flying at a constant speed of
8.0 m/s. What is the bird’s kinetic energy?
ž  Energy
that is stored as a result of position or
shape and has the potential to do work.
Why are these pictures examples of potential
energy?
ž  Potential
energy that depends upon an
object’s height.
ž  Depends on its mass, height, and
acceleration due to gravity.
POTENTIAL ENERGY FORMULA:
PE= mgh
ž  mass is in kg
ž  Gravity is 9.8 m/s2
ž  Height in meters
ž  PE in J (joules)
ž  A
diver at the top of a 10 m high platform
has a mass of 50 kg. What is her gravitational
potential energy?
ž  The
potential energy of an object that is
stretched or compressed.
ž  The
major forms of energy are mechanical
energy, thermal energy, chemical energy,
electrical energy, electromagnetic energy,
and nuclear energy.
ž  Energy
associated with the motion and
position of everyday objects.
ž  Sum of the object’s potential and kinetic
energy
ž  The
total potential energy of all the
microscopic particles make up its thermal
energy.
ž  When atoms move faster, the thermal energy
increases and objects become warmer.
ž  The
energy stored in the chemical bonds in
compounds.
ž  When the bonds are broken, energy is
released to do work.
ž  Example: Car burning gasoline to move.
ž  The
energy associated with electric charges.
ž  Example: lightning, calculators
ž  Form
of energy that travels through space in
the form of waves.
ž  Ex: visible light, UV rays, X-rays
ž  The
energy stored in atomic nuclei.
ž  Ex: Nuclear fission and fusion