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Motion
Observing
To observe an object in motion, you must usea referenced object. The one sitting still is consideredto be the reference point.
When an object changes position over time, comparedto the reference point, the object is said to be in motion
When an object is at rest, what is its speed?
2 mph
1 mph
3 mph
0 mph
0%
87%
7%7%
1. 2 mph
2. 1 mph
3. 3 mph
4. 0 mph
Motion is change in ____.
speed
velocit
y
eyelin
er
position
56%
11%6%
28%
1. speed
2. velocity
3. eyeliner
4. position
A reference point for determining position and motion could be
Cloud
Building
A movin
g objec..
.
All of t
he abo...
0%
28%
61%
11%
1. Cloud
2. Building
3. A moving object
4. All of the above
Chemistry
Inertia is a function of mass.
Inertia - tendency of an object to resist changes in its direction
In other words an object stays at rest untilsomething causes it to move
Small objects have small inertiaMassive objects have large inertia
Inertia
A person in a head-on car collision who is not wearing a seat belt continues to move forward at
the original speed of the car because of ____.
Inerti
a
Balance
d force
Grav
ity
Dru
nk driv
er
44%
0%
39%
17%
1. Inertia
2. Balanced force
3. Gravity
4. Drunk driver
Which one of the following objects has the greatest inertia?
pencil
Bowling b
all
Baseball
Your head
6% 6%11%
78%1. pencil
2. Bowling ball
3. Baseball
4. Your head
Motion
Speedthe rate at which an object moves
two variables need to be considereda. distanceb. time
therefore:
speed = distance time (s)
The distance traveled divided by the time it took to travel that distance determines an
object's
Acceleration
Position
Speed
Force
35%
0%
59%
6%
1. Acceleration
2. Position
3. Speed
4. Force
The SI unit for speed is
Km/foot
feet/s
econd
meter/s
econd
mile
/hour
0%
62%
23%15%
1. Km/foot
2. feet/second
3. meter/second
4. mile/hour
Motion
Average speed is a measure of the distance traveled in a given period of time; it is sometimes referred to as the distance per time ratio. Suppose that during your trip to school, you traveled a distance of 5 miles and the trip lasted 0.2 hours (12 minutes). The average speed of your car could be determined as
MotionVelocitythe speed of an object in a particular directionFor example: 15 m/s east
or 22 m/s southwest
velocity always includes which way; N, S, E or W
Velocity is determined by speed and direction
True
False
25%
75%1. True
2. False
Motion
Resultant velocitythis calculation is determined as follows
How fast is the boy moving?a. if velocity is in the same direction
e.g.
b. if velocity is in opposite directionse.g.
If a bus is traveling south at 15 mph and a boy stands and walks north at 1 mph what is
the resultant velocity
15 mph
1 mph
14 mph
16 mph
0% 0%
100%
0%
1. 15 mph
2. 1 mph
3. 14 mph
4. 16 mph
If a bus is traveling south at 15 mph and a boy stands and walks south at 1 mph what
is the resultant velocity
15 mph
1 mph
14 mph
16 mph
6%
56%
33%
6%
1. 15 mph
2. 1 mph
3. 14 mph
4. 16 mph
Motion
Accelerationis the rate at which velocity changes
to apply a force to an object to make it either slow-down,speed-up or change direction.
To calculate acceleration:
Acceleration = final velocity– starting velocity time it takes to change velocity (s)
= mps s
Motion
What is the acceleration of a dragster that goes from 0 to 300 mps in 5 seconds?
100 mph/s
600 mph/s
60 mps/s
50 mph/s
6%
28%
56%
11%
1. 100 mph/s
2. 600 mph/s
3. 60 mps/s
4. 50 mph/s
The acceleration of an object
1. Does n
ot de...
2. is al
ways o...
3. is al
ways i...
4. None of t
he...
6%
44%
28%22%
1. Does not deal with force
2. is always opposite of the force that was applied.
3. is always in the same direction as the force.
4. None of the above
Acceleration of an object
Slows d
own wit.
..
Incre
ases w
ith...
Is in
the sa
me...
All of t
he abo...
18%
53%
6%
24%
1. Slows down with increase in weight
2. Increases with force
3. Is in the same direction
4. All of the above
Observe the animation of the three cars below. Which car or cars (red, green, and/or blue) are undergoing an acceleration? Study each car individually in order to determine the answer.
Now that you've answered the first question correctly, try this one: which car (red, green, or blue) experiences the greatest acceleration?
As a final test of your understanding, consider the position-time graph at the right. Each one of the three lines on the position-time graph corresponds to the motion of one of the three cars. Match the appropriate line to the particular color of car.
Motion
either a push or a pull
Unbalanced forceproduces a change in acceleration
net force is greater than zero
Balanced forceproduces no acceleration
net force is zero
Force
Motion
Net force is the combination of 2 forces
A force is which one of these?
Push Pull
Push or P
ull
None of t
he ab...
6% 0%
94%
0%
1. Push
2. Pull
3. Push or Pull
4. None of the above
When two birds are pulling on a worm and the worm moves toward the first bird, you
know that the forces are ____.
Balance
d
Unbalance
d
Action-re
actio...
Unfair
0% 0%6%
94%1. Balanced
2. Unbalanced
3. Action-reaction
4. Unfair
Which of the following is NOT an example of a force being exerted?
Pushing open a...
Sitti
ng in a c.
..
Texting
None of t
he ab...
0%
65%
18%18%
1. Pushing open a door
2. Sitting in a chair
3. Texting
4. None of the above
Balanced forces applied to an object makes that object
Stay a
t rest
Change directi
on
Accelerate
Slows d
own
65%
24%
6%6%
1. Stay at rest
2. Change direction
3. Accelerate
4. Slows down
You have made a house of cards on top of your table. Suddenly, a gust of wind blows through an open window and your house of cards comes tumbling down. The wind
applied ____ to your house of cards.
Grav
ity
Balance
d
Fricti
on
Centipedal
Unbalance
d
28%
0%
39%
11%
22%
1. Gravity
2. Balanced
3. Friction
4. Centipedal
5. Unbalanced
hills and valleys
Motion
force that opposes motion between twosurfaces that are touching
Greater the force, greater the friction
Friction
The force that opposes motion
Grav
itational
Balance
d
Unbalance
d
Fricti
on
36%
57%
0%7%
1. Gravitational
2. Balanced
3. Unbalanced
4. Friction
One way to increase friction is to use
wax
wate
r sa
nd oil
7%
21%
57%
14%
1. wax
2. water
3. sand
4. oil
MotionGravity and Motion
all objects fall to the ground at the same rate
how? difference in force is canceled by the difference in mass
What would hit first, elephant or feather?
Motion
Air resistance slows down acceleration
air resistance continues to increase until it matchesthe downward force of gravity
object then falls at a constant velocitycalled terminal velocity
Motion
Another example of terminal velocity
Remember, the increase in air resistance continuestill it is even with gravity
Motion
Free fallno air resistance
can only occur in a vacuum
the only force acting is gravity
Motion
Three laws that relate force to the motion of objects
First law aka. law of inertiaAn object at rest tends to stay at rest and an
object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Newton’s Laws of Motion
Examples of Newton’s 1st Law
Newton’s first law of motion applies
Moving objects
No m
oving obje...
Speed
Both 1 and 3
0% 0%0%0%
1. Moving objects
2. No moving objects
3. Speed
4. Both 1 and 3
CountdownCountdown
10
According to Newton’s first law of motion, a moving object that is not acted on by an
unbalanced force will
Remain in m
oti... St
op
Blow up
Accelerate
0% 0%0%0%
1. Remain in motion
2. Stop
3. Blow up
4. Accelerate
CountdownCountdown
10
Newton’s first law of motion states that an object stays at rest unless a(n) ____ acts on
it.
Balance
d force
Grav
itational ..
.
Unbalance
d for..
.
Fricti
on force
0% 0%0%0%
1. Balanced force
2. Gravitational force
3. Unbalanced force
4. Friction force
CountdownCountdown
10
Motion
Second Law due to unbalanced forcethat the acceleration of an object is dependent
upon two variables a. the net force acting upon the object and b. the mass of the object
Examples of Newton’s 2nd Law
MotionThird Law
that for every action (force) in nature, there is an equal and opposite reaction; force pairs
in other words: if object A exerts a force on object B, then object B also exerts an equal force on object A
note: we are only talking about forces
Examples of Newton’s 3rd Law
Motion
Momentumproperty of a moving object that dependson the object’s mass and velocity
in other words: more momentum an object has theharder it is to stop the object
Conservation (constant) of momentumThat is, the momentum lost by object 1 is equal to the momentum gained by object 2
MotionEnergy
the ability to do work
remember, work is a transfer of energy so thereforework only occurs if the force and motion are in the same direction
Work = F x d; force times distance
since force is in Newtons (N) and distanceis in meters the new label is J or Joules
Motion
Energy of Motioncalled kinetic energy
as long as an object is moving there is kinetic energy
kinetic energy depends on mass and velocity
creating work
MotionEnergy of position
called potential energy
gravitational potential energy depends on weight and height
tells us about stored energy that has thecapacity to do work
Motion
Mechanical energykinetic energy + potential energy
as the height decreases the PE also decreases
as the speed increases so does the kinetic energy
MotionTypes of energy
MotionConservation of energy
energy can be neither created nor destroyedtotal amount of energy in a closed system is always the same
with conversion of energy you always get thermal energy
what are the energies in the rollercoaster ride?
Motion
Temperature temperature depends on the kinetic energyof the particles
as a substance gets hotter, it’s particles moves faster
Motion
Temperature conversion
Motion
Heattransfer of energy between objects of different temperatures
energy is transferred from higher temperatures tolower temperatures
Motion
Types of energy transfer
a. conduction – heat transfer by direct contacthigher kinetic energy to lowerkinetic energy
b. convection – heat transfer by movementof liquid or gas
c. radiation – heat transfer as electromagnetic waves