Download Unit 5 Motion, Heat, and Forces

UNIT 5
MOTION, HEAT, AND
FORCES
MRS. MATTHEWS
JAN. 20-
MOTION
NOTES, FORMULA TRIANGLE FOLDABLE, PRACTICE, AND QUIZ
OBJECTIVES
ARE DISTANCE AND TIME IMPORTANT
WHEN DESCRIBING MOTION?
ESSENTIAL QUESTION
MOTION
Motion occurs when an object changes position
relative to a reference point.
Distance: how far an object has traveled
Displacement: Distance & direction of an objects
change in position from starting point.
Distance vs. Displacement
Speed - the distance an object travels per unit time = rate
of change in position
Average Speed (v) = total distance (d)/total time (t)
Speed
INSTANTANEOUS
• Description: speed at any given point in time
• Example: Driving a car looking down at the
speedometer.
AVERAGE
• Description: Total distance traveled divided by total
time traveled.
• Example: Taking a road trip.
CONSTANT
• Description: speed that does not vary
• Example: putting a car on cruise control
ARE DISTANCE AND TIME IMPORTANT
WHEN DESCRIBING MOTION?
BOTH DISTANCE AND TIME ARE IMPORTANT.
• Time (t) – measured period in which action
persists.
CALCULATE = divide speed into distance
t=d/v
TIME (t)
*The distance an object travels per unit time. Rate
of change in position.
*Units – m/s, cm/s, km/s
*CALCULATE = Divide distance by time
v = d/t
SPEED (v)
* How far an object has traveled.
* Units – cm, m, km
CALCULATE – speed x time
d=vxt
DISTANCE (d)
SPEED FORMULA TRIANGLE PRACTICE
1. 12 km/hr
2. 1.15 hr
3. 171 miles/hr
4. 1,125 km
5. 6 miles/min
DESCRIBING MOTION
QUIZ
TAPE QUIZ IN NOTEBOOK AFTER IT IS GRADED.
DESCRIBING MOTION ANSWER KEY
1. B
2. D
3. E
4. C
5. A
6. 5 m/s
7. 1.09 hrs
8. 7.5 m/s
ACCELERATION
NOTES, PRACTICE, QUIZ
OBJECTIVES
ESSENTIAL QUESTION
• What is the difference between
positive and negative acceleration?
ACCELERATION
• Velocity – includes speed of an object and the direction of
the motion.
• What is the difference between speed and velocity?
• Acceleration - rate of change of velocity. Acceleration
occurs when an object changes speed, its direction, or
both.
USE DOCUMENT CAMERA TO POST
FORMULAS
MAKE SURE TO ADD 2 TO ACCELERATION
ESSENTIAL QUESTION
• What is the difference between
positive and negative acceleration?
• If speed increases, acceleration is
positive. If speed decreases,
acceleration is negative.
ACCELERATION PRACTICE PROBLEMS
Find
Velocity
Initial
Velocity
Time
(t)
1
26 m/s
20 m/s
6s
2
0 km/s
12 km/s
4s
3
8 m/s
3 m/s
2s
4
46.4 m/s
27.3 m/s
11 s
5
5 m/s
15 m/s
5s
PRACTICE PROBLEM ANSWERS
1. 1
6. 30
2. -3
7. 9.4
3. 2.5
8. -1.5
4. 1.74
9. 1
5. -2
MOTION & FORCES
PAGE 8-9
WHAT DOES THE FORCE OF FRICTION
BETWEEN TWO OBJECTS IN CONTACT
DEPEND ON?
ESSENTIAL QUESTION
OBJECTIVES
FORCES
• Force – a push or pull applied to an object.
• Net Force – when two or more forces act on an object
at the same time.
MOTION & FORCES
Forces are =
balanced forces
Net force = 0
Forces unbalanced
Net force = +
Combined forces
Net force = 2 forces
added together
FRICTION
• Friction- the force that opposes the sliding motion
of two touching surfaces.
• Friction is caused by microscope bumps on surfaces
called microwelds.
Type of
Friction
Description
Example
Static
Friction in which two surfaces are not Pushing a fridge across the
moving past one another.
floor.
Sliding
Friction where two objects slide past
one another.
Friction between a rolling object and
surface it rolls on.
Rolling
Fluid
Sledding down a hill.
Skateboard moving on ground.
Skydiving
Friction when objects moves through
fluid, meaning either a liquid or gas.
AIR RESISTANCE
• Friction is like force that opposes motion of
objects that move through air – depends on
speed, size, and shape of object
ESSENTIAL QUESTION
• What does the force of friction between two objects
in contact depend on?
• Kinds of surfaces and the friction pushing them
together.
TYPES OF FRICTION PG. 8
• Create a Four Point Envelope Foldable.
• Label
• Write definitions
• Draw an illustration
• Glue/tape to top of page
• Tape extra piece onto page 14 for future use
NEWTON’S LAWS OF MOTION
PAGE 10-11
NEWTON ESTABLISHED
HIS THREE LAWS OF
MOTION TO DO WHAT?
ESSENTIAL QUESTION
OBJECTIVES
NEWTON’S FIRST LAW OF MOTION
• Also known as Inertia!
• An object in motion stays in motion or an object at rest
stays at rest until an unbalanced net force acts upon
it.
• Inertia – tendency of an object to resist change in its
motion.
• Draw stationary ball, rolling ball into wall (look at notes)
NEWTON’S SECOND LAW OF MOTION
• A net force acting on an object causes the object to
accelerate in the direction of the force.
• Force = mass X acceleration
F=mXa
• Acceleration is determined by size of force and the
mass of an object.
NEWTON’S THIRD LAW OF MOTION
• For every action (force) there is an equal or
opposite reaction (force).
• Momentum – property of moving object
resulting from its mass an velocity.
Momentum (p) = mass X velocity
ESSENTIAL QUESTION
• Newton established his three laws of motion to do
what?
• Newton’s Laws can be used to analyze and predict
changes in motion on objects.
NEWTON’S COMIC STRIP
• Draw a 6 framed comic strip illustrating one of
Newton’s Laws.
• Recommend using a rough draft page. Final copy
is in the INB.
GRAVITY
PG. 12-13
What causes the path of a projectile to be covered?
Essential Question
Objectives
GRAVITY
• Gravity – any two masses that exert an attractive
force on each other.
• Gravity depends on mass and distance between
objects.
• Weight – gravitational force exerted on an object,
measured in units called Newtons
PROJECTILE MOTION
• Projectile is anything thrown or shot through the
air.
• A projectile follows a curved path and has either
horizontal or vertical motion.
CENTRIPETAL FORCE
• Centripetal Acceleration – acceleration toward the
center of a curved or circular path.
• Centripetal force– force toward the center of a
curved or circular path.
What causes the path of a projectile to be covered?
The path is covered by the vertical motion and horizontal
motion.
PATH OF PROJECTILES
PG. 12
THE NATURE OF ENERGY
PG. 14-15
OBJECTIVES
ESSENTIAL QUESTION
• What is the difference between kinetic
and potential energy?
ENERGY
• ENERGY – the ability to cause change.
• Forms of energy include:
• Electrical
• Chemical
• Thermal
• Radiant
KINETIC ENERGY
• Kinetic Energy – energy in the form of motion
• KE depends on mass and velocity of moving objects
• Example: Going down a slide
POTENTIAL ENERGY
• Potential Energy – energy that is stored
• Example of PE: waiting at the top of the slide
• Elastic Potential Energy – energy that is stored by
something that can stretch or compress such as a rubber
band or string.
POTENTIAL ENERGY
• Chemical Potential Energy – energy stored in chemical
bonds.
• **A glass of milk has CPE until you drink it, then calories
are used as energy for your body.
• Gravitational Potential Energy – anything that can fall
has stored GPE.
• ***A ball on a ledge.
ESSENTIAL QUESTION
• What is the difference between kinetic and
potential energy?
• Kinetic energy is energy in form of motion where
potential energy is stored.
ENERGY VOCABULARY FLIPBOOK
PG. 14
CONSERVATION OF ENERGY
PG. 16-17
ESSENTIAL QUESTION
• What law states that the total amount of
energy never changes?
NATURE OF ENERGY QUIZ
TAPE ONTO PG. 14
OBJECTIVES
ENERGY
• Energy can be transformed from one form to another.
• Example:
•
Lightbulb (Electric Energy)
• Light Energy
• Thermal Energy
MECHANICAL ENERGY
• total amount of kinetic energy and potential
energy in a system.
• ME = PE + KE
THE LAW OF CONSERVATION OF
ENERGY
• - energy may change form, but it cannot be created or
destroyed under ordinary conditions.
THE LAW OF CONSERVATION OF
ENERGY
• Friction converts mechanical energy in to thermal
energy
• The breakfast you eat converts chemical energy
into mechanical energy, heat energy so you r
muscles can pump your legs.
• Air resistance converts ME into thermal energy.
ESSENTIAL QUESTION
• What law states that the total amount of
energy never changes?
• The Law of Conservation of Energy.
CONSERVATION OF ENERGY
FILMSTRIP
PG. 16
FILMSTRIP DIRECTIONS:
• Cut out television and center square from the handout.
• Tape/Glue TV on top of existing TV. Please read directions and DO
NOT attach on sides.
• After coloring illustrations on filmstrip, cut out filmstrip and slide
behind television to see your illustration on the big screen.
• Write an explanation explaining your filmstrip on a separate sheet
of paper and attach to pg. 17. Make sure you share how energy
changed form.
TEMPERATURE & HEAT
PG. 18-19
OBJECTIVES
TEMPERATURE
• Temperature -a measure of the average value of the
kinetic energy of the molecules in random motion. (SI
unit for temperature is Kelvin (K)).
• Thermal Expansion- almost all substances expand when
they are heated and contract when they are cooled –
*Exception water
• Thermal Energy- sum of the kinetic and potential energy
of all the particles in an object; thermal energy of an object
increases as temperature increases.
HEAT
• Heat - thermal energy that flows from something
at a higher temperature to something at a lower
temperature.
• Specific Heat- amount of heat needed to raise the
temperature 1kg of some material by 1’C.
THERMAL ENERGY EQUATION
• Q. change in thermal energy (J) = mass (kg) X temp (‘C) X
(‘C)
• Specific heat (J/(Kg)(c)
• Q = m (Tf – Ti) C
SPECIFIC HEAT OF COMMON
MOLECULES
Specific Heat of
Common Molecules
Substance
Water
Wood
Carbon
Glass
Iron
Specific Heat
(J/(kg’C)
4,184
1,760
710
664
450
KINETIC ENERGY LAB
• FOLLOW DIRECTIONS
• Or you will loose the lab
KINETIC ENERGY LAB
• Matter, which is made up of tiny particles (atoms &
molecules), is all around you. Those particles are in
constant motion moving in all directions at different
speeds. The measure of the average kinetic energy of
those particles is temperature, which increases as the
kinetic energy of the particles increases.
MATERIALS
• 2 – 200 ml beakers
• Water
• Food coloring
• Timer
DIRECTIONS
1. Pour 150 ml of room temperature water into
Beaker A.
2. Pour 150 ml of hot water into Beaker B.
3. Put one drop of food coloring into each beaker.
Record observation.
DIRECTIONS CONT.
4. Compare the two beakers for the next two minutes.
At the end of each minute draw a colored sketch
showing the water in each beaker in your data table.
5. Write a paragraph describing the results of your
experiment. Make sure to use the following
vocabulary in your description: water molecules,
kinetic energy, temperature.
TEMPERATURE & HEAT QUIZ
TAPE ONTO PAGE 18
TRANSFERRING THERMAL ENERGY
PG. 20-21
OBJECTIVES
ESSENTIAL QUESTIONS
• How are conduction and convection different?
TRANSFERRING THERMAL ENERGY
Conduction
transfer of energy
by thermal energy
between particles in
matter
Convection
transfer of thermal
energy in a fluid
movement of warmer
and cooler fluid from
place to place
Radiation
transfer of energy by
electromagnetic waves
CONDUCTION
• Conduction occurs in solids, liquids, and gases.
• Metal is the best conductor of heat.
CONVECTION
• Convection occurs in fluids.
• Rising of warmer fluid and sinking of cooler fluid
forms a convection current.
TRANSFER HEAT
• The transfer of energy by radiation is most important in
gases.
• Insulator- material in which heat flows slowly.
• EXAMPLES of best insulators: wood, some plastics,
fiberglass, and air.
Using Heat
Page 22-23
OBJECTIVES
ESSENTIAL QUESTION
• Why can’t heat be converted completely to work?
FORCED AIR SYSTEM
• most common type of heating using a furnace to
heat air then a fan blows air through ducts to
rooms.
RADIATOR SYSTEMS
• closed metal container that contains hot water or
steam which is transferred to surrounding air by
conduction this warm air moves through rooms by
convection.
ELECTRIC HEATING SYSTEMS
• electronically heated coils placed in floors
and in walls heating surrounding air by
conduction.
SYSTEMS USING SUN’S ENERGY
• Passive Solar Heating- radiant energy from the Sun is
transferred to the room through windows.
• Active Solar Heating- systems that use solar collectors
that absorb radiant energy from the Sun.
THERMODYNAMICS
study of the relationship among thermal energy,
heat, and work.
1st Law of
Thermodynamics
2nd Law of
Thermodynamics
The increase in thermal
It is impossible for heat to flow
energy of a system equals
from cool object to warm object
the work done on the system unless work is done.
plus the heat transferred to
the system.
ESSENTIAL QUESTION
• Why can’t heat be converted completely to work?
• The 2nd Law of Thermodynamics prevents it.