Transcript Energy - Google Sites

EOCT Review
What is Energy?
Question:
• Energy is the ability to do
 How does work.
ENERGY and • Work is a transfer of
energy….
WORK work
 WHEN WORK IS
together?
DONE…..
THE SAME AMOUNT OF
ENERGY IS INVOLVED.
Roller Coaster….. Where is the
Kinetic Energy and Potential Energy:
 Before watching the roller coaster. Note what you think happens to the K and P
energy of the roller coaster at each point.
http://www.classzone.com/books/ml_science_share/vis_sim/mfm05_pg126_coaster/
mfm05_pg126_coaster.html
Point:
How Much Potential/Kinetic Energy
A
More Potential as rollercoaster goes up….Height of hill
goes to max potential. Very little Kinetic energy.
Hits max. kinetic at end of slope.
The height of the hill is not as larger, has less Potential
energy than hill A
Going down the hill – has Kinetic Energy
Upside down more potential but almost the same
Down the hill – Kinetic
B
C
D
E
F
Notice the size of the hill determined how much the potential
and kinetic energy it has.
The Energy of MOTION :
That’s Kinetic!
The Energy of Position:
That’s Potential!
 All moving objects have kinetic
energy
 Doesn’t
 Kinetic energy DEPENDS on
SPEED and MASS
 Gravitational Potential Energy
DEPENDS on WEIGHT and HEIGHT
 Kinetic Energy = MV² / 2
 Gravitational Potential Energy =
Weight * Height
involve motion
EVERYTHING has POTENTIAL
ENERGY….even if it is still….
M= Mass V= Speed
 More MASS = More Kinetic
Energy
 More WEIGHT = More Potential
Energy
Stop and Think
1.Why does it take longer for a car to stop
when applying the brakes at a speed of 60
mph than at 50 mph?
2.What is the kinetic energy of a 0.5-kg ball
travelling at a speed of 300 m/sec?
3.All forms of energy can exist as either
_________ or ___________ energy.
4.T/F Energy is the performance of work.
Mechanical Energy
Total energy of motion and position of an object
Mechanical Energy = potential energy + kinetic energy
Potential Energy
Kinetic Energy
So…. What happens to the kinetic energy
if your potential energy decreases?
*It increases!
Energy: Ability to do work. Objects can GAIN energy by
work done n them, and energy can convert from one
form to another. Energy is measured in joules.
Can you list
and describe
the 6 forms
of energy?
Energy: Ability to do work. Objects can GAIN energy by
work done n them, and energy can convert from one
form to another. Energy is measured in joules.
Forms of Energy:
Thermal
Chemical
Electrical
Sound
Light
Nuclear
Thermal Energy
Particles are in motion –
Kinetic energy
Thermal Energy: total
energy of the particles
that make up an object.
The faster particles
move the more Kinetic
energy…. If they are
moving faster then the
particles have more
space….
C
H
E
M
I
C
A
L
Chemical Energy is POTENTIAL ENERGY…
This energy is required to bond atoms together.
Example: Your body breaks the chemical bonds
in food to provide energy to YOU!
E
N
E
R
G
Y
el
e
Energy of electric
charges….
 Energy of moving
electrons
 Electrical energy is
POTENTIAL Energy…
and Kinetic Energy.
c
t
r
i
c
a
l
Energy
SOUND Energy
Caused by objects vibration.
Form of Potential and Kinetic
energy
Example: Guitar
The strings store potential energy
Once released, the strings move
back to the position--- kinetic
Light Energy:
Is produced by the vibrations of electrically charged
particle.
Nuclear Energy:
The change in the nucleus of the atom.
Produced in 2 ways:
• when 2 or more nuclei join
together
• when the nucleus splits apart
Energy Conversions
• Law of Conservation of Energy – energy is not
__________ nor ___________, it only changes
form
• Every time an energy conversion takes place a
little bit of energy is always “wasted”
(converted into) _____________ energy
EOCT Practice
1. Which of the following could be used to
convert light energy to electrical energy?
A a windmill
B a chemical storage battery
C a solar cell
D rotating coils in a magnetic field
C.Like a solar calculator
EOCT Practice
2. Which of the following situations violates the
law of conservation of energy?
A A ball dropped from the top of a building
increases in speed until it hits the ground.
B A block sliding freely on level ice increases in
speed until it hits a wall.
C A child playing on a swing moves fastest at the
bottom of the swing’s path.
D The height a ball bounces decreases with each
bounce
A. f = ma . Newton’s 2nd law. Eventually should hit
terminal velocity and will fall at a constant velocity
(speed) until it hits the ground
EOCT Practice
3. Albert stirs a mug of hot chocolate with a
metal spoon. What type of heat transfer is
responsible for the spoon getting hot?
A conduction
B convection
C thermoelectric
D radiation
A. Direct contact = conduction
EOCT Practice
4. The stored energy in a battery
can BEST be described as
A thermal
B chemical
C nuclear
D kinetic
B. Also would be direct current
once it is used in a circuit
EOCT Practice
5. In a restaurant kitchen, lamps are used to
keep food warm. Which type of
electromagnetic radiation do the lamps
emit that is primarily responsible for
keeping the food warm?
A gamma
B. Infrared means “heat” wave.
B infrared
C ultraviolet
D visible
EOCT Practice
6. Which energy transformation takes place
when a match is struck against the side of a
matchbox and bursts into flames?
A electrical energy
light energy
B heat energy
kinetic energy
C chemical energy
heat energy
D potential energy
electrical energy
C.
EOCT Practice
7. Conduction can BEST be described as the
transfer of heat energy by
A waves traveling through empty space
B fluids traveling through other fluids
C gases expanding within a fluid medium
D atoms colliding with their neighbors
D. Collide = touching!