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PSc.3.1.2
Energy Notes
EQ: How are kinetic energy and potential energy related?
EQ: What is the law of conservation of energy?
Vocabulary
Word
Dictionary
Own Words
Mechanical
system
A mechanical system manages power
to accomplish a task that involves
forces and movement.
Something that has
to do with forces
and motion
Kinetic Energy
energy that a body possesses by
virtue of being in motion.
Energy caused by
motion.
KE = 0.5mv2
Picture/Motion
Potential
Energy
the energy possessed by a body by
virtue of its position relative to others,
stresses within itself, electric charge,
and other factors.
Energy that relates
to the height of an
object.
PE = mgh
Conservation
of Energy
a principle stating that energy cannot
be created or destroyed, but can be
altered from one form to another.
Energy changes
form, but is not
made or destroyed.
Heat
the quality of being hot; high
temperature.
How hot something
is
Friction
the resistance that one surface or
object encounters when moving over
another.
Opposes a motion
Kinetic Energy
-The energy caused by motion.
-KE = 0.5mv2
-The unit for energy is Joules (J).
-The two factors that affect kinetic energy are mass and velocity.
-When did your balloon rocket have kinetic energy?
-Where did you see the highest kinetic energy on your skate park?
-Where did you see the lowest kinetic energy on your skate park?
1. What would be the kinetic energy of bird with a mass of 20 kg and
a velocity of 6 m/s?
2. What would be the kinetic energy of a skater with a mass of 5 kg and a velocity of 12 m/s?
3. Which would have a higher kinetic energy?
A.
A roller coaster with a mass of 50 kg and a velocity of 10 m/s.
B.
A roller coaster with a mass of 10 kg with a velocity of 20 m/s.
C.
I need more information to answer.
-Answer: _______ because ____.
Potential Energy
-The energy caused by position (or height).
-PE = mgh (g = 9.8 m/s2)
-The unit for energy is Joules.
-The three factors that affect potential energy are mass, acceleration due to gravity, and height.
-When did your balloon rocket have potential energy?
1. What would be the potential energy of bird with a mass of 20 kg and is flying 30 m above the ground?
2. What would be the potential energy of a skater with a mass of 5 kg and is
at the top of a halfpipe, 100 m above the ground?
3. Which would have a greater potential energy?
A.
A roller coaster with a mass of 50 kg and a velocity
of 10 m/s and near the top of a hill.
B. A roller coaster with a mass of 50 kg with a velocity
of 20 m/s and at the bottom of a hill.
C. I need more information to answer.
-Answer:
-Which would have a greater potential energy?
A.
An owl in a tree that has a weight of 10 N.
B.
An owl on the ground that has a weight of 20 N.
C.
I need more information.
Conservation of Energy
-Energy is not created or destroyed, it just changes form.
-The total energy is called mechanical energy (because we are dealing with a mechanical system).
-When friction is NOT involved, KE + PE = ME
**Kinetic energy and potential energy change throughout a system, but the total
mechanical energy does NOT change.