Motion
Table of Contents
Describing and Measuring Motion
Slow Motion on Planet Earth
Acceleration
Motion
Learning Objectives
1. Determine when an object is in motion.
• Key terms: reference point, relative motion, displacement
2. Calculate an object’s speed and velocity.
• Key terms: average speed, instant speed, speed & direction,
velocity
3. Demonstrate how to graph motion.
• Key terms: slope = rise/run = rise divided by run = vertical
movement divided by horizontal movement on a graph
Motion
Graphing Motion Experiment (Part 1)
Goal- To create 4 distance vs. time graphs that correspond
to the 4 below. Distance (d) is on the y-axis.
1
2
3
4
d (m)
Time (s)
Time (s)
Time (s)
Time (s)
Background- What is your reference point for this
experiment? (What are you measuring the distance
from?)
Hypothesis- Describe how you think you will need to move
for EACH of the 4 distance-time graphs.
Motion
Graphing Motion Experiment (Part 1)
Results- Sketch your distance-time graphs and describe how you
moved for each line segment of the graph.
Conclusion- In complete sentences and using the motion sensor
as your reference point, describe how you would move (or not
move) for…
1. A horizontal line on a distance-time graph.
2. A slanted line going down and to the right on a distance-time
graph.
3. A curved line curving up and to the right on a distance-time
graph.
4. What happens to the slope of the graph if a person moves
faster?
5. What does the graph look like if a person is moving at a
constant rate or speed?
Motion
Learning Objectives
1. Determine when an object is in motion.
• Key terms: reference point, relative motion, displacement
2. Calculate an object’s speed and velocity.
• Key terms: average speed, instant speed, speed & direction,
velocity
3. Demonstrate how to graph motion and how to interpret the
graph.
• Key terms: slope = rise/run = rise divided by run = vertical
movement divided by horizontal movement on a graph
Motion - Describing and Measuring Motion
Determining When an Object is in Motion
Have you ever watched a
large truck pass you on the
highway and felt like you were
going backwards?
Whether or not an object is in
motion depends on the
reference point you choose
& if the distance between the
object and the reference point
is changing.
Figure 2- Page 8
Motion
Negative Distance & Football
Question: Can a distance be negative in
relationship to a reference point?
Football Example: Reference point in
football (below), positive play (right), negative
play- sacked for a loss (bottom right)
Motion
Which of the following is true if you are riding your
bike past the middle school?
A. You are moving relative to the bike, but not the school.
B. You are not moving relative to the school or the bike.
C. You are moving relative to the school, but not relative to
the bike.
D. You are moving relative to the bike and the school.
Motion
Suppose you are driving, and you are pulled over by
a cop. The cop explains that his radar gun
measured you as going 30 mph in a 65 mph zone.
He also tells you that he used his radar gun while
driving down the highway. Using physics, how do
you get out of getting a ticket for driving too
slowly?
A. Explain that he graduated from Penns Valley.
B. Explain that since he was moving, your speed is relative
to his speed. This makes it seem like you were driving
slowly.
C. Explain that since he was moving, your speed is relative
to his speed. This makes seem like you were driving fast.
D. Explain that you never drive slowly. You always drive
fast.
Motion
How would a position-time graph appear for an
object at that is not moving?
A.
B.
C.
D.
A straight horizontal line
A slanted line moving up and to the right.
A curved line curving up and to the right.
A slanted line moving down and to the left.
Motion
Which of the following distance-time graphs shows
a person moving closer to a reference point?
A.
B.
C.
D.
Graph 1
Graph 2
Graph 3
None of the graphs below.
1
2
3
d (m)
Time (s)
Time (s)
Time (s)
Motion
Which of the following shows a person moving at a
constant rate?
A.
B.
C.
D.
E.
Graph 1 only.
Graph 2 only.
Graph 3 only.
Graphs 1 & 2.
Graphs 1, 2, and 3.
1
2
3
d (m)
Time (s)
Time (s)
Time (s)
Motion
Which of the following shows a person moving the
fastest away from the reference point?
A.
B.
C.
D.
Graph 1
Graph 2
Graph 3
None of the above.
2
1
3
d (m)
Time (s)
Time (s)
Time (s)
Motion - Describing and Measuring Motion
Calculating Speed
What is an example of a speed that a fast car can go?
So, how can you calculate speed? If you travel 45 km in 3 hours,
what is your average speed?
Speed = change in distance/change in time
Instant speed is your speed at a certain time.
Average speed is your averaged speed for the ENTIRE trial,
event, or race.
Avg. speed = change in distance/change in time
Motion
Speed vs. Velocity Experiment
Scenario (do not need to write): Markie is jogging at 6.0 mph, while Suzy is also
jogging at 6.0 mph. However, Markie’s velocity is -6.0 mph while Suzy’s is 6.0
mph. Why are their speeds the same, but their velocities are different?
Goal: Determine the difference between SPEED and VELOCITY.
Hypothesis: What do you think is the difference between speed and velocity?
General Procedure (Handheld procedure done as a group beforehand):
1. Using the velocity-time graph’s (x,y) coordinates at the top of the graph screen,
determine each person’s VELOCITY while moving away from the motion
sensor. Be sure to check if the velocity is positive or negative.
2. Using the velocity-time graph’s (x,y) coordinates at the top of the graph screen,
determine each person’s VELOCITY when moving back toward the motion
sensor. Be sure to check if the velocity is positive or negative.
Results: Organize the VELOCITIES FOR EACH PERSON in a DATA TABLE.
Motion
Speed vs. Velocity Experiment
Conclusion (answer in complete sentences):
•
Were there any negative velocities? Why is this the case? Is
velocity just speed? If not, what else is factored in to velocity?
Hint- Think about when your velocity was negative relative to the
motion sensor, and keep in mind that speed is NEVER negative.
Scenario: Markie is jogging at a speed of 6.0 mph, while Suzy is also
jogging at a speed of 6.0 mph. However, Markie’s velocity is -6.0 mph
while Suzy’s is 6.0 mph. Why are their speeds the same, but their
velocities are different?
Velocity = speed + direction relative to a reference point
So, Markie was going just as fast as Suzy, but in the opposite direction.
Peregrine Falcons can dive
at speeds up to 242 mph.
Motion - Describing and Measuring Motion
Graphing Motion (Calculating speed)
You can show the motion of an object on a line graph in
which you plot distance versus time. Remember: Velocity is
the change in distance in a certain direction during a
certain length of time. So, velocity or speed = rise/run
Motion
Graphing Motion Experiment (Part 2)
In your lab notebook, match up each of the 4 distance-time graphs with one of the
velocity graphs below. Sketch each of the graphs below and designate which
velocity-time graph corresponds to which distance-time graph.
Use your descriptions of speed or rate from Graphing Motion (Part 1) for help.
BE SURE TO CAREFULLY ANALYZE WHAT HAPPENED TO DISTANCE &
DIRECTION AND WHAT IS HAPPENING TO VELOCITY FOR THE DURATION
OF DATA COLLECTION TIME FRAME! V = velocity
A
B
C
V
(m/s)
Time (s)
D*
Motion
Graphing Motion Experiment (Parts 1 & 2)
1
2
3
4
d (m)
Time (s)
C
Time (s)
A
Time (s)
D*
V
(m/s)
Time (s)
Time (s)
B
Motion
Distance Determination (from a Speed-Time Graph)
SPEED 5 m/s
(m/s)
1s
2s
Time (s)
How far will the object have gone in 2 seconds?
10 meters (5 m/s x 2 s)
Or
Determine the area under the line: Create a rectangle
and determine its area (l x w = 2 s x 5 m/s = 10 m)
Motion
Jebediah runs 6 miles in 1 hour (60 minutes). His
average speed is 6 mph. However, at minute 45, his
speed was 4.5 mph. Which of the following would
best explain what happened?
A. He was probably running faster at minute 45 than he was
for most of the jog.
B. He got more energy from drinking 5 Red Bulls before
jogging.
C. He was running up a hill and had to slow down.
D. He wore out his running shoes.
Motion
Explain what happened between 0 and 4 minutes in
terms of the person’s speed. Keep in mind, the
graph is a DISTANCE-TIME graph.
A.
B.
C.
D.
The person moved at a constant speed
The person stopped moving.
The person slowed down.
The person moved faster.
Motion
What is the velocity of the object based upon the
data in the graph below? Assume time is in
seconds.
A.
B.
C.
D.
50 m/s
10 m/s
5 m/s
50 m
Motion
How is velocity different from speed?
A. Velocity involves instant and average speed, so it will be
positive.
B. Speed involves direction as well, so it can be negative.
C. They’re the same.
D. Velocity involves direction as well, so it can be negative.
Motion
Which of the following may only be a measurement
of speed?
A.
B.
C.
D.
-0.001 mm/s
-2 m/s
27 mph
100 km/h East
Motion
Which of the following is a measurement of
velocity?
A.
B.
C.
D.
32 rpm (revolutions per minute) clockwise
100 km/h Northeast
-2.7 m/s
All of the above.
Motion
Suzy is moving East at a velocity of 7 mph from her
house. Markie moved 14 miles West from Suzy’s
house in 2 hours. What is Markie’s velocity?
A.
B.
C.
D.
7 mph
-7 mph
6 mph East
-6 mph
Motion
If you are running at 5 mph, then how far will you
run in 4 hours at the same pace?
A.
B.
C.
D.
25 miles
5 mph
20 miles
15 miles
Motion
How far will the object go in 4 seconds (using the
graph below)?
A.
B.
C.
D.
0 meters
4 meters
8 meters
12 meters
SPEED
(m/s)
2 m/s
2s
4s
6s
Time (s)
Motion
Noggin Knockers from p. 15- 1a, 1c, 2b, 2c, 3a, & 3b
[9 points- Homework Grade]
1-
(a) Car- not moving
(b) Road- not moving since the distance between
you and the road is not changing;
(c) Stop Sign- moving away or toward it. (1 point per
part for 3 points total).
2- Velocity = speed + direction (2 points)
3- Slope and Speed = 600 meters/3 minutes = 200 m/min (2
points- 1 point for the correct value, 1 point for the correct
units).
4- Distance = Speed x time = area under the line = 10 m/s x
3 s = 30 m (2 points- 1 point for value, 1 point for correct
units)
Motion
Softball vs. Baseball Reaction Times
Big Question: Is it tougher to hit a baseball than a softball?
Baseball data:
95 mph fastball = 139.33 ft/.sec.
Distance from the pitcher’s mound = 60.5 ft.
Time it takes ball to get to the plate (t) = ?
Set up a proportion (t = time): 1 sec. / 139.33 ft. = t / 60.5 ft.
t = .434 seconds
*Note that it is slightly more time than the actual reaction time because
the pitcher launches the ball about 5.5 feet in front of the mound!
Once this release point is taken into account, the reaction time is 0.395
seconds.
Motion
Softball vs. Baseball Reaction Times
Big Question: Is it tougher to hit a baseball than a softball?
Softball data:
72 mph softball = 105.6 ft/.sec.
Distance from the pitcher’s mound = 43 ft.
Time it takes ball to get to the plate (t) = ?
Set up a proportion (t = time): 1 sec. / 105.6 ft. = t / 43 ft.
t = .407 seconds
*Note that it is slightly more time than the actual reaction time
because the pitcher launches the ball about 6 feet in front of the
mound!
Once this release point is taken into account, the reaction time is
0.350 seconds.
Motion
Graph Matching (No lab write-up)
Goal- Determine who can match the graph the best and how
they were able to do it.
Motion
End of Section:
Describing and
Measuring
Motion
Motion - Slow Motion on Planet Earth
Earth’s Plates
According to the theory of plate tectonics, Earth’s
landmasses have changed position over time
because they are part of plates that are slowly moving.
Motion - Slow Motion on Planet Earth
Plate Movement
Some plates move at a rate of several centimeters each
year. Others move only a few millimeters per year.
Motion - Slow Motion on Planet Earth
Continental Drift Activity
Click the Active Art button to open a browser window and
access Active Art about continental drift.
Motion - Slow Motion on Planet Earth
Previewing Visuals
Before you read, preview Figure 8. Then write two questions
that you have about the diagram in a graphic organizer like
the one below. As you read, answer your questions.
Previewing Figure 8
Q. How have the positions of the continents changed over time?
A. The distance between the continents has increased.
Q. What causes Earth’s plates to move?
A. Slow-moving currents beneath Earth’s outer layer cause the
plates to move.
Motion
End of Section:
Slow Motion on
Planet Earth
Motion
Learning Objectives
1. Describe the motion of an object as it accelerates.
•
Key Terms: acceleration, change in velocity over
time, increasing vs. decreasing speed, change in direction
2. Calculate acceleration.
• Key Terms: change in velocity over time
3. Describe how graphs are used to analyze the motion of an
accelerating object.
• Key Terms: Velocity vs. Time graph, Distance vs. Time
Graph, slope
Motion - Acceleration
Calculating Acceleration
What does it mean if a car accelerates? Have you ever heard of a
car that can go 0 to 60 mph in about 6 seconds? (Just like mine).
What about when a car decelerates?
To determine the acceleration of an object moving in a straight line,
you must calculate the change in velocity per unit of time
Average Acceleration = (final velocity – starting velocity)/time
Motion - Acceleration
Graphing Acceleration
You can use both a speed-versus-time graph and a distanceversus-time graph to analyze the motion of an accelerating
object.
Motion
Velocity vs. Acceleration Experiment
Goal: Create the 3 velocity-time graphs below and determine which
acceleration vs. time graphs they correspond to. Keep in mind that your
graphs will be more rigid, but the general pattern should be the same.
Hypothesis: Determine how you think you should move for EACH of the 3
graphs (BY ONLY MOVING AWAY).
Results: Sketch your velocity-time graphs (hit the F2 button once and
press up to adjust the scale), describe how you moved for each one,
and match them up with the correct acceleration vs. time graphs. Use
your descriptions for help.
I
V (m/s)
Time (s)
II
Time (s)
III
Time (s)
Motion
Velocity vs. Acceleration Experiment
A
(m/s2)
0
A
B
0
C
0
Time (s)
Conclusion (answer in complete sentences):
1. How did you move for 0 or no acceleration?
2. How did you move for a constant positive acceleration?
3. How did you move for a constant negative acceleration (or deceleration)?
4. What is the independent or manipulated variable for the graphs above?
What is the dependent or responding variable for the graphs above?
Also, note which axis (x or y) the variables are on.
Motion
Velocity vs. Acceleration Match-Up
A
(m/s2)
B
A
0
C
0
0
Time (s)
III
II
I
V (m/s)
Time (s)
Time (s)
Time (s)
Motion
Learning Objectives
1. Describe the motion of an object as it accelerates.
•
Key Terms: acceleration, change in velocity over
time, increasing vs. decreasing speed, change in direction
2. Calculate acceleration.
• Key Terms: change in velocity over time
3. Describe how graphs are used to analyze the motion of an
accelerating object.
• Key Terms: Velocity vs. Time graph, Distance vs. Time
Graph, slope
Motion - Acceleration
Graphing Acceleration
You can use both a speed-versus-time graph and a distanceversus-time graph to analyze the motion of an accelerating
object.
Motion - Acceleration
Calculating Acceleration
To determine the acceleration of an object moving in a straight line,
you must calculate the change in velocity per unit of time.
Average Acceleration = (final velocity – starting velocity)/time
Motion - Acceleration
Calculating Acceleration
As a roller-coaster car starts down a slope, its speed is 4 m/s. But 3
seconds later, at the bottom, its speed is 22 m/s. What is its
average acceleration?
Read and Understand
What information have you been given?
Initial speed = 4 m/s
Final Speed = 22 m/s
Time = 3 s
Motion - Acceleration
Calculating Acceleration
As a roller-coaster car starts down a slope, its speed is 4 m/s. But 3
seconds later, at the bottom, its speed is 22 m/s. What is its
average acceleration?
Plan and Solve
What quantity are you trying to calculate?
The average acceleration of the roller-coaster car = __
What formula contains the given quantities and the unknown
quantity?
Acceleration = (Final speed – Initial speed)/Time
Perform the calculation.
Acceleration = (22 m/s – 4 m/s)/3 s = 18 m/s/3 s
Acceleration = 6 m/s2
The roller-coaster car’s average acceleration is 6 m/s2.
This is a positive acceleration (speeding up).
Motion - Acceleration
Calculating Acceleration
As a roller-coaster car starts down a slope, its speed is 4 m/s. But 3
seconds later, at the bottom, its speed is 22 m/s. What is its
average acceleration?
Look Back and Check
Does your answer make sense?
The answer is reasonable. If the car’s speed increases by 6 m/s
each second, its speed will be 10 m/s after 1 second, 16 m/s after 2
seconds, and 22 m/s after 3 seconds.
Motion - Acceleration
Calculating Acceleration
Practice Problem
A certain car brakes from 27 m/s to rest in 9 seconds.
Find the car’s average acceleration.
(0 m/s – 27 m/s ) ÷ 9 s = -27 m/s ÷ 9 s = -3 m/s2
This is a negative acceleration, which is also called a
deceleration (slowing down)
Motion
Acceleration Practice Problems:
Determine Each Object’s Acceleration
1. A car travels at 28 m/s (a little over 60 mph) and stops at a red
light in 4 seconds.
2. A person starts jogging at 6 km/h and ends up jogging at 10 km/h
in 30 minutes. You may need to convert units.
3. Your car goes from rest to 30 m/s in half a minute.
Motion
Noggin Knockers
Motion
Noggin Knockers
Motion
Noggin Knockers
Motion
Learning Objectives
1. Describe the motion of an object as it accelerates.
•
Key Terms: acceleration, change in velocity over
time, increasing vs. decreasing speed, change in
direction
2. Calculate acceleration.
• Key Terms: change in velocity over time
3. Describe how graphs are used to analyze the motion of an
accelerating object.
• Key Terms: Velocity vs. Time graph, Distance vs. Time
Graph, slope
Motion
Changing Directions
When riding in a car, have you ever changed directions by going around a
curve or turn in the road at a “high” speed? Did you feel your body push
towards the outside of the curve?
Another example would be riding on those amusement park rides that
spin around quickly.
This is an acceleration too (Centripetal Acceleration = the object you’re in
is being pulled towards the middle of the circle while you feel pushed
toward the outside of the circle).
Motion
Which of the following is not an example of a
positive or negative acceleration?
A. Going from jogging to running during the last 30 seconds
of a 5K race.
B. Jebediah rides his horse and buggy at a constant speed
of 5 mph for an entire 10 minutes on a straight road.
C. A car braking due to traffic.
D. A car turning around on the highway.
Motion
Which of the following is an example of a positive
acceleration?
A. A bus coming to a stop.
B. A car peeling out of the parking lot like Mr. Snyder on
Fridays at 3:15 PM.
C. A rollercoaster braking.
D. A person standing still.
Motion
Which of the following is an example of a negative
acceleration?
A.
B.
C.
D.
A skateboarder taking off from rest to a speed of 5 m/s.
A truck going at a constant speed of 65 mph.
A bus coming to a stop after a tractor stops in front of it.
A car speeding up in the passing lane.
Motion
Which of the following is an example of 0 or no
acceleration?
A.
B.
C.
D.
A bowling ball slowing down when it hits the 10 pins.
A car speeding up to pass another vehicle.
A bus coming to a stop.
A person riding a bike at 15 mph for 2 hours on a straight
path because there is nothing better to do in Bald Eagle.
Motion
Determine the acceleration of the object from the
graph below.
A.
B.
C.
D.
6 m/s/s
2 m/s/s
10 m/s/s
5 m/s/s
Motion
If you measure velocity in miles per hour and time
in hours, then what would be the units for
acceleration?
A.
B.
C.
D.
Miles per hour per hour (Miles/h/h or Miles/hr/hr)
Miles per hour (mph)
Hours (h or hr)
Hours squared per mile (hr2/mile)
Motion
Determine the acceleration if a roller coaster starts
from rest and reaches a speed of 27 m/s in 3
seconds.
A.
B.
C.
D.
9 m/s or 9 mps
-81 m/s/s or -81 m/s2
9 m/s/s or 9 m/s2
-9 m/s/s or -9 m/s2
Motion
A roller coaster goes from a speed of 27 m/s to rest
in 3 seconds. What is the rollercoaster’s
acceleration?
A.
B.
C.
D.
9 m/s or 9 mps
-81 m/s/s or 81 m/s2
9 m/s/s or 9 m/s2
-9 m/s/s or -9 m/s2
Motion
A car is traveling at 20 mph and after 10 seconds,
the car is moving at 20 mph. What is its average
acceleration?
A.
B.
C.
D.
-2 m/s/s or -2 m/s2
2 m/s/s or 2 m/s2
0 m/s/s or 0 m/s2
It cannot be calculated.
Motion
Markie is riding the Tilt-a-Whirl at an amusement
park. He is spinning around at a constant speed of
4 m/s. Which of the following is true?
A. He never accelerates during the entire ride.
B. His ride car accelerates towards the inside of the circular
spin.
C. He decelerates as the ride spins around.
D. He will get sick while on the ride.
Motion
Noggin Knockers (7 points)p. 27: 1a, 1c, 2b, 3b, 3c, 4
1 (2 points)- The skater is accelerating by changing
direction/spinning/going in a circular pattern.
2 (2 points)- (15 m/s – 0 m/s)/10 seconds = 1.5 m/s/s
3 (1 point)- Object is decelerating/negatively
accelerating/slowing down
4 (2 points)- (9 m/s – 18 m/s)/3 seconds = -3 m/s/s
Motion
Velocity vs. Acceleration Extension
Goal- Create the velocity-time graphs below and describe how
you moved for each one.
Time (s)
Time (s)
Time (s)
0
V
(m/s)
IV
V
VI
Procedure Help: Switch to Velocity-time graph and use the F2
and up buttons to “stretch” the graph to the appropriate scale.
Conclusion (in complete sentences): What was the main
difference with your motion in the creation of the graphs in this
experiment compared to the ones in the Velocity vs. Acceleration
Experiment?
Motion
Motion Practice Test
1. If the distance between that object and the reference pt.
is changing.
2. Sidewalk- not moving; tree-moving
3. To be drawn
4. 100 m/20 s = 5 m/s
5. No
6. Speed and direction
7. To be drawn
8. Acceleration
9. Slowing down- running then stopping, approaching a red
light, etc.
Motion
Motion Practice Test (Continued)
10. Velocity units = m/s, time units = seconds
11. Acceleration
12. Speed or velocity
13. Slowing down
14. 1 minute = 60 seconds; (120 m/s – 60 m/s)/60 s = 1
m/s/s
15. To be drawn
16. Man./Ind. variable (x-axis) = time; Res./Dep/ variable (yaxis) = distance
17. Rise/Run, determine the slope of the line
18. 3 m/s x 5 s = 15 meters
19. (0 m/s – 20 m/s)/5 s = -20 m/s divided by 5 s = -4 m/s/s
Motion - Acceleration
Identifying Main Ideas
As you read the section “What is Acceleration?”, write the
main idea in a graphic organizer like the one below. Then
write three supporting details that further explain the main
idea.
Main Idea
In science, acceleration refers to...
Detail
Increasing speed
Detail
Decreasing
speed
Detail
Changing
direction
Motion - Acceleration
Links on Acceleration
Click the SciLinks button for links on acceleration.
Motion
End of Section:
Acceleration
Motion
Graphic Organizer
Motion
is described
relative to a
is measured by
Reference
point
Distance
÷ Time
equals
Speed
in a given
direction is called
Velocity
Motion
End of Section:
Graphic Organizer