Material on Final Exam Section 1 Measuring Motion Objectives Describe the motion of an object by the position of the object in relation to a reference point Identify the two factors that determine speed ID: 704712
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Slide1
Chapter 5: Matter in Motion
Material on Final ExamSlide2
Section 1: Measuring Motion
Objectives:
Describe the motion of an object by the position of the object in relation to a reference point
Identify the two factors that determine speed
Explain the difference between speed and velocity
Analyze the relationship between velocity and acceleration
Explain how changes in motion can be measured and represented in a graphSlide3
Section 1: Measuring Motion
Everything moves
Even if it does not look like it
When we see things
move
, it is based on a
_______________________________________ is when an object changes position over time relative to a reference point
Our reference point is THE _____________
(usually)
reference point
EARTH
MotionSlide4
1/26 Agenda
Continue Notes:
How to solve Velocity math problems
Practice calculating speed, time, and distance
Begin some HW problems for practice
HW:
Pg 1: items I, II, IIIPg 2, and Pg 3Slide5
Section 1: Measuring Motion
What is speed?
_________
is the distance traveled by an object divided by the time taken to travel the distance
SI unit is _________
Other units: mi/h, km/h,
ft/s
Speed
m/sSlide6
Section 1: Measuring Motion
Average Speed
For the __________ time
=
total distance
total time
General speedFor a _________ time = distance time
s
d
t
WHOLE
shortSlide7
Section 1: Measuring Motion
Write the formula
Identify knowns and unknowns
Plug in numbers
“Chug”: Solve and circle
What is the average speed for the whole trip?Slide8
Section 1: Measuring Motion
Write the formula
Identify knowns and unknowns
Plug in numbers
“Chug”: Solve and circle
A snail moves 1m in 100 seconds. What is the speed
?Slide9
Section 1: Measuring Motion
Write the formula
Identify knowns and unknowns
Plug in numbers
“Chug”: Solve and circle
A car is driving along at 25km/hr. How long will it take me to drive 400km?Slide10
Section 1: Measuring Motion
Write the formula
Identify variables
Plug in numbers
Solve and circle
A bee is flying by at a speed of .75 m/s. How far will the bee travel in 60 seconds?Slide11
Section 1: Measuring Motion
Speed
≠
Velocity
_____________
is the speed of an object in a given directionVelocity MUST include a ___________!
Velocity
directionSlide12
Section 1: Measuring Motion
Which is it? Speed or Velocity?
7 miles per hour
2.345 inches/minute east
18.7
ft
/s down7.77 km/daySlide13
Section 1: Measuring Motion
Changes in Velocity
Could be a change in the actual ________
Could be a change in ______________
Could be _________!
speed
direction
bothSlide14
Section 1: Measuring Motion
Combining Velocities
When you combine velocities together, you have to look at the
direction
If they are in the same direction, you ______ them
If they are in different directions, you ______________ THEM
***MAKE SURE TO INCLUDE THE DIRECTION***
ADD
SUBTRACTSlide15
Section 1: Measuring Motion
Combining velocities
I walk 3
ft
/s down while the escalator pushes me 5
ft/s up. What is the resultant velocity?
A bird is flying at a velocity of 5km/hr west when a gust of wind pushes her with a velocity of 10 km/hr west. What is the resultant velocity?Slide16
Section 1: Measuring Motion
Distance-Time graphs
This type of graph is based on the most basic things we need to know about the motion of an object
(______________
and
_________).
Time goes on the ___ axisPosition / Distance goes on the ___-axisIF the object moves _________ from start, we __________________ distance (+)IF the object moves ____________ start, we ____________ distance (-)
Draw each section a bit at a timeNo best fit lines!
distance
time
XY
away
increase
toward
decreaseSlide17
Section 1: Measuring MotionSlide18
What is happening from 0-30 seconds?
What is happening from 0-60 seconds?
From 60-75 seconds?
From 75-90 seconds?
From 90-105 seconds?
105 to 120?
120 to 135?135 to 150?Section 1: Measuring MotionSlide19
What is the speed of the dancer from…
30 to 60 seconds?
90 to 105 seconds?
135 to
150 seconds?
Section 1: Measuring MotionSlide20
Section 1: Measuring Motion
Acceleration
Does ________ always mean “
speed up”!
___________________
is the rate at which velocity changes
An object accelerates if its speed, direction, or both change
not
AccelerationSlide21
Section 1: Measuring Motion
Increase in velocity
________________________
Do not say “speeding up”
Decrease in velocity
__________________________
Do not say “slowing down”
Positive acceleration
Negative accelerationSlide22
Section 1: Measuring Motion
Calculating Average Acceleration
Units for acceleration:__________
How?
m
= m x 1 = m s s x s s2
s
m/s
2Slide23
Section 1: Measuring Motion
Math Practice
Use the equation for
average acceleration
to do the
following problem.A plane passes over point
A at a velocity of 240 m/s north. Forty seconds later, it passes over point B at a velocity of 260 m/s north. What is the plane’s average acceleration?Write the formulaShow your workSolve with correct numberInclude correct unitsSlide24
Section 1: Measuring Motion
Math Practice—Solving for Acceleration (
a
)
A roller coasters velocity at the top of the hill is 10 m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26m/s. What is the acceleration of the coaster?Slide25
Section 1: Measuring Motion
Math Practice—Solving for time (
t
)
How long will it take a car to go from 0 to
45
km/hr if they are accelerating at 5 km/hr2?Slide26
Section 1: Measuring Motion
Math Practice—Solving for starting/initial velocity (
v
i
)
You roll a bowling ball for 4
s. The ball traveled at a constant acceleration of 2 m/s2 down the lane and was traveling at a speed of 9 m/s by the time it reached the pins at the end of the lane. How fast was the ball going when it left Tim’s hand?Slide27
Section 1: Measuring Motion
Math Practice—Solving for final velocity (
v
f
)
If a
truck, with an initial velocity of 10 m/s, accelerates at a rate of 30 m/s2 for 3 seconds, what will its final velocity be?Slide28
Section 1: Measuring MotionSlide29
Section 1: Measuring Motion
Recognizing Acceleration on a Graph
Velocity has to CHANGE over timeSlide30
Section 1: Measuring Motion
Circular Motion: Continuous Acceleration
You are always changing direction in a circle!
_________________ _____________________
is the acceleration that occurs during
circular motion
Not “speeding up” (Positive acceleration)Not “slowing down” (Negative acceleration)But ____________________!
Centripetal
acceleration
c
hanging directionSlide31
Section 1: Measuring Motion
Please answer the following questions on your objective sheet
Describe the motion of an object by the position of the object in relation to a reference point
Identify the two factors that determine speed
Explain the difference between speed and velocity
Analyze the relationship between velocity and acceleration
Explain how changes in motion can be measured and represented in a graphSlide32
Section 2: What is a Force?
Objectives
Describe forces, and explain
how forces
act on objects
.
How do you determine the net force when more than one force is acting on an object?Compare balanced and unbalanced forces.Describe how unbalanced forces cause changes in motion.Slide33
Section 2: What is a Force?
What is a force?
A
force
is a _______ or _________ exerted on an object in order to change the direction of the object
Often causes a change in motion
Unit of force is the _______________
push
pull
Newton (N)Slide34
Section 2: What is a Force?
Forces
Any time you push or pull an object, you are exerting a force.
However, a _________________________________________!
a
force does not guarantee movementSlide35
Section 2: What is a Force?
Unseen Forces and Receivers of
Force
Sometimes we ______________ the forces
that are in place
Gravity
MagnetismStatic electricity
c
annot seeSlide36
Section 2: What is a Force?
Determining
Net Force
The
net force
is the combination of _______________________ acting
on an objectSAME direction? _______!OPPOSITE direction? ____________
Add
Subtract
all of the forcesSlide37
Section 2: What is a Force?
Balanced and Unbalanced Forces
Look at the
________________
to see if forces are balanced or
not
If the net force is zero…
The forces are _________________!No change in motion
If the net force is not zero…The forces are ________________!There is a change in motion
net forces
balanced
unbalancedSlide38
Section 2: What is a Force?
Please answer the following on your objective sheet
Describe forces, and explain
how forces
act on objects
.
How do you determine the net force when more than one force is acting on an object?Compare balanced and unbalanced forces.Describe how unbalanced forces cause changes in motion.Slide39
Section 3: A Force that Opposes Motion
Please answer the following on your objective sheet
Describe friction
Explain why friction occurs
List the two types of friction, and give examples of eachSlide40
Section 3: A Force that Opposes Motion
Why does it stop?
Unbalanced force!
____________
is a force that opposes motion between two surfaces that are in contact
Everything has a ________ surface
rough
FrictionSlide41
Section 3: A Force that Opposes Motion
The microscopic view of surfaces shows little hills and valleys
When they come in contact with each other, they stick together and slow down the movementSlide42
Section 3: A Force that Opposes Motion
What is the difference?
The ______________________________!
More _____________ = more _____________
weight
weight
frictionSlide43
Section 3: A Force that Opposes Motion
Rough surfaces and friction
The ________________ the surface, the more hills and valleys the two items can get “stuck” on
rougherSlide44
Section 3: A Force that Opposes Motion
Types of
Friction
Kinetic Friction
Friction between _____________ surfaces
_____________
_____________Static FrictionFriction between ________________ objects_____ movement because forces are balanced
moving
Sliding
Rolling
nonmoving
NoSlide45
Section 3: A Force that Opposes MotionSlide46
Section 3: A Force that Opposes Motion
Friction: Harmful and Helpful
No friction?
Could not push tires against ground to move car
Could not use brakes to stop car
With friction?
Car parts rub against each other and wear outPart of everyday life!Writing, holes in socks, slipping on ice, climbing a hillSlide47
Section 3: A Force that Opposes Motion
Please answer the following on your objective sheet
Describe friction
Explain why friction occurs
List the two types of friction, and give examples of eachSlide48
Section 4: Gravity—A force of Attraction
Objectives
Describe gravity and its effect on matter
Describe the difference between mass and weightSlide49
Section 4: Gravity—A force of Attraction
What is gravity?
Gravity
is a force of _______________ between objects that is due to their masses
Gravity can affect an object by…
Changing its ________
Changing its __________________Changing its speed _______ direction
attraction
speed
direction
ANDSlide50
Section 4: Gravity—A force of Attraction
The Effects of Gravity on Matter
All objects have ________
All objects experience an ______________ towards one another due to gravity
Why don’t we get
sucked
into other people, items, or objects?
______________________________
We do not have enough mass!
mass
attractionSlide51
Section 4: Gravity—A force of Attraction
Newton and the study of gravity
Newton was able to recognize that items falling and the moon in orbit are caused by
_________________
Newton’s Law of Universal Gravitation
describes the relationship between gravitational _________, _______, and ____________
Applies to everything in the universe!
gravity
force
mass
distanceSlide52
Section 4: Gravity—A force of Attraction
Law of Universal
Gravitation
Part 1:
_______________________ ______________________________
Part 2
: ________________________ ________________________________________________________
Gravitation force increases as mass increases
Gravitation force decreases as distance increasesSlide53
Section 4: Gravity—A force of Attraction
Weight as a measure of Gravitational Force
Weight and mass are
______________________
Mass
—the amount of _________ in an object (kg)
Weight—measure of ________________________________ on an object (N)
not
the same
gravitational force
massSlide54
Section 4: Gravity—A force of Attraction
Weight can be calculated using the formula
Units
Weight: ______________
Mass: _______________
If in grams, must _______________
Gravity: _______
On Earth, the value is _________________
Kilograms (kg)
Newtons
(N)
convert
m/s
2
9.8 m/s
2Slide55
Section 4: Gravity—A force of Attraction
Math Practice: Solving for Weight (
w
)
A cat has a mass of 7 kg. What would the weight of the cat be on Earth?Slide56
Section 4: Gravity—A force of Attraction
Math Practice: Solving for mass (
kg
)
On a trip to Mars, you meet an alien. When
you bring it back to Earth, you find that it weighs
245 N on Earth. What is the mass of the alien?Slide57
Section 4: Gravity—A force of Attraction
Math Practice: Solving for gravity (
g
)
The same alien from before (mass of 25 kg) says he only weighs 90N on his home planet. What is the gravity on Mars?Slide58
Section 4: Gravity—A force of Attraction
Please answer the following on your objective sheet
Describe gravity and its effect on matter
Describe the difference between mass and weight