Download Kinetic energy - Mrs. Wiedeman

Chapter 4
Energy
What is energy?
Def: ability to cause _________________
 Every change involves
_______________________

Different Forms
_________________________
 _______________________ – stored in
food, involved in reactions
 _______________________– gives off
 _______________________ – heat
 Same thing just different forms

Kinetic Energy
Def: energy of a __________________ object
 Depends on _________________ and
_________________


Kinetic energy (Joules) = 1 mass (kg) x [speed (m/s)]2
2
KE = 1 mv2
2
 SI unit for energy is ______________________

Practice!
What is the kinetic energy of a .15 kg baseball
moving at 40 m/s.
 A car moving at a speed of 20 m/s has a kinetic
energy of 300,000 J. What is the car’s mass?

Potential Energy
Even ______________________ objects
have energy
 _____________________ in the object,
has potential to change
 Def: ________________ energy

Elastic Potential Energy
Def: ___________________ energy by
something that can _________________
or compress
 Stretched rubber band – elastic potential
energy  _________________ energy

Chemical Potential Energy
Def: energy stored in _____________________
bonds
 Food, gasoline, etc.

Gravitational Potential Energy

Def: stored energy by objects due to position
___________________ earth (able to fall)
Practice!
Find the height of a .15 kg baseball that
has a GPE of 73.5 J.
 Find the GPE of a .3 kg coffee mug on a
1-m high counter.

What could you do to change GPE?
 Change _______________ or __________

Section 2
Conservation of Energy
Changing Forms of Energy
Changing electrical energy –> electricity –>
light and heat energy
 Energy is ______________________ changing
forms

Transforming Chemical Energy
Cars – ______________________ energy
transformations
 Spark plug – ____________________ – engine wheels

Transforming Chemical Energy

_________________ plants – take in
_____________________ and transform
to chemical energy in plants
Mechanical Energy

Def: total amount of ________________
and ______________________ energy
Mechanical Energy = Potential + Kinetic
Falling Objects

As potential  kinetic,
__________________
energy stays same

Potential _________ =
kinetic _____________
Projectile Motion
Mechanical energy remains _________________
 Still see _________________________ of
energy

Swinging

Best part is falling
from highest point

High GPE = Low KE

Describe transition…
Law of Conservation of Energy




Def: ___________________ can not be
created or destroyed
Energy just changes _________________
All energy in the
________________________ does not
change
Energy in = Energy out
Is energy always conserved?
Swinging – you eventually will stop – where
does all the energy go?
 ____________________ – air resistance =
thermal energy

Human Body – Energy Relations
What forms of energy are in your body?
 Conservation of energy still true
 Food, fat = __________________ energy
 Activity = ___________________ energy
 Calorie 1C = 4,184 J

Chapter 6 Section 1
Temperature and Heat
Matter in Motion
______________________ is made of tiny
particles in _______________________ motion
 have kinetic energy
 Faster = ________________ kinetic energy

Temperature
Def: measure of ________________
kinetic energy of particles
 High Temp. = ______________ Energy
 Low Temp. = _______________ Energy
 Unit  Kelvin

Thermal Energy
_____________________ between air and
butter particles increase energy of butter =
____________________ temperature
 Def: ________________ of kinetic and potential
energy of particles in object

Thermal Energy
As temp ___________________ = thermal
energy increases
 If object has MORE __________________ and
at the same temp. has HIGHER thermal energy

Heat
Is your seat toasty?
 Def: ________________ energy that
flows from something at a
_________________ temp to a lower
temp
 Unit: Joule

Beachin’ it up!
How can there be extreme differences in
temperature from air, _______________
and water?
 Sun rays are the same why different
temp?
 Sand heats up ______ times faster than
water

Specific Heat

Specific Heat: heat needed to raise
___________ of material by 1C
Water as a Coolant
It’s _______________ specific heat – absorb a
lot of heat ________________ changing temp
much
 ______________ bonds have to be broken
before particles move really fast
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