Motion - asfa.k12.al.us · Determine when an object is in motion. • Key terms: reference point,...

Motion Key Words: Time, Observer, Frame of reference , Position, Distance,

Displacement, Speed, Velocity, Acceleration, Direction, Vector, Motion Diagram, Motion Graph, One-Dimensional Motion,

MOTION :1-13-15Todays Learning Objectives1. 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

MOTIONDISCUSSION OF ASSIGNMENT:

Physical science by Little

(Blue Book)

Page C10 to C36

What you learn in the reading assignment:

• 1:1:An object in motion changes position

• 1:2: Speed measures how much distance changes

• 1:3: Acceleration measures how fast _______changes

SUMMARY OF CONCEPTS IN MOTION 1:1:An object in motion changes position

Motion is change in ___________over time e.g. jumping as you time yourself

A position describe location of an object

Describe an example or relative motion and reference frame

A reference frame describe location of an observer of motion

How many numbers would you describe your location e.g. street address to somebody?

A position is compared to a _______point

A location to which you compare other locations is called a ____________

A position can be described using ____and direction

1:2: Speed measures how much ___________changes

Displacement include distance_____ and _____

1:2 Velocity include _speed________ and ___________

A vector is a quantity that has both ____and ______

1:3: Acceleration measures how fast _______changes

1:3 speed direction can change in time

1;3 direction can change in time

1:3 both speed and direction can change in time

Motion can be represented by motion graphs and motion

diagrams

Example: distance time graph / velocity time graph,

MOTION

• https://phet.colorado.edu/en/simulation/legacy/moving-man

http://www.compadre.org/precollege/items/detail.cfm?

ID=9346

Interactive Simulations by American association of physics teachers

Interactive Simulations by Phet

Interactive Simulations by The Physics Classroom

MOTION: ACTIVITIES

• SIMULATION, STUDENT DEMOSTRATION AND EXPERIMENT

• ACT/EXPLORE---OBSERVE---THINK---DISCUSS:

• MATERIALS: Rubber balls, tossing ball up and down, books to make incline plane,

• Internet Activities for the moving man, motion detectors or timers (smartphone will do), Pasco or Vernier sensors

• NOTE: ALWAYS SAVE YOUR CLASS VIDEOS; WE MIGHT MAKE A CLASS WEBSITE FOR CLASS EXPERIMENTS, LABS ETC

MOVING (MOTION) MAN ASSIGNMNET 1-13-15:

Objective: to learn how to simulate the moving man phet simulations

Requirements: Smartphone, tablet or laptop with java.

Instructions: The moving man: google “phet simulation” -----then select physics -----then select motion---then select the moving man

• OR: LearN how to use moving man by watching the video “Understanding Velocity Graphs using the PhET -Moving Man-Simulation” (https://www.youtube.com/watch?v=xmCvpsQRKyo )

The Phet website is provided below:

(http://phet.colorado.edu/en/simulation/legacy/moving-man)

On the Introduction, Set initial position to be zero (o): Initial velocity to be (1m/s) and acceleration to be (0). Then start and plot the graphs of position vs. time, velocity vs. time and acceleration vs. time.

Sketch the graphs in your note book and turn it in tomorrow for credit.

You may Go to Chart Tab draw the graphs plotted by software.

https://www.youtube.com/watch?v=xmCvpsQRKyo

http://phet.colorado.edu/en/simulation/legacy/moving-man

http://phet.colorado.edu/en/simulation/legacy/moving-man

ACTIVITIES FOR Thursday 1-14-2016:

• Simulating position, velocity and acceleration using motion “PhetInteractive Simulation”

• Motion Graphs using PheT simulations: Come with your electronic devices (smartphone, laptop or tablet with java)

• Experiments : Motion Graphs Using Vernier Motion Detectors and LabQuest2

• Experiments: Motion Graphs Using Lap top Computer With Data Studio Software, Pasco Motion Detectors with Interphase, and Pasco Motion detectors

• If you like, you may go ahead and review the PowerPoint lectures. A sample test is given at the end of the PowerPoint.

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.

• 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.

d (m)

Time (s) Time (s)Time (s)

1 32 4

Time (s)

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?

Learning Objectives1. 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

- 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.

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)

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.

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.

How would a position-time graph appear for an object at that is not moving?

A. A straight horizontal line

B. A slanted line moving up and to the right.

C. A curved line curving up and to the right.

D. A slanted line moving down and to the left.

Which of the following distance-time graphs shows a person moving closer to a reference point?

A. Graph 1

B. Graph 2

C. Graph 3

D. None of the graphs below.

Time (s)Time (s) Time (s)

d (m)

1 2 3

Which of the following shows a person moving at a constant rate?

A. Graph 1 only.

B. Graph 2 only.

C. Graph 3 only.

D. Graphs 1 & 2.

E. Graphs 1, 2, and 3.


d (m)

1 2 3

Which of the following shows a person moving the fastest awayfrom the reference point?

A. Graph 1

B. Graph 2

C. Graph 3

D. None of the above.


d (m)

12 3


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

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.

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.


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

Graphing Motion Experiment (Part 2)• (PASCO OR VERNIER MOTION SENSOR ACTIVITIES)

• match up each of the 4 distance-time graphs with one of the velocity graphs below. Sketcheach 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

V

(m/s)

Time (s)

A B C D*

Graphing Motion Experiment (Parts 1 & 2)

d (m)

Time (s) Time (s)Time (s)

1 32 4

Time (s)

V

(m/s)

Time (s)

A BD*C

Distance Determination (from a Speed-Time Graph)

• 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)

5 m/s

1 s 2 s

SPEED

(m/s)

Time (s)

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.

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. The person moved at a constant speed

B. The person stopped moving.

C. The person slowed down.

D. The person moved faster.

What is the velocity of the object based upon the data in the graph below? Assume time is in seconds.

A. 50 m/s

B. 10 m/s

C. 5 m/s

D. 50 m

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.

Which of the following may only be a measurement of speed?

A. -0.001 mm/s

B. -2 m/s

C. 27 mph

D. 100 km/h East

Which of the following is a measurement of velocity?

A. 32 rpm (revolutions per minute) clockwise

B. 100 km/h Northeast

C. -2.7 m/s

D. All of the above.

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. 7 mph

B. -7 mph

C. 6 mph East

D. -6 mph

If you are running at 5 mph, then how far will you run in 4 hours at the same pace?

A. 25 miles

B. 5 mph

C. 20 miles

D. 15 miles

How far will the object go in 4 seconds (using the graph below)?

A. 0 meters

B. 4 meters

C. 8 meters

D. 12 meters

2 m/s

2 s 4 s

SPEED

(m/s)

Time (s)

6 s

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 partfor 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)

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.

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 timebecause 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.

Graph Matching (No lab write-up)

• Goal- Determine who can match the graph the best and how they were able to do it.

End of Section:Describing and Measuring Motion

Learning Objectives1. 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

- 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

Graphing Acceleration

• You can use both a speed-versus-time graph and a distance-versus-time graph to analyze the motion of an accelerating object.

- Acceleration

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.


V (m/s)I II

III

Velocity vs. Acceleration Experiment

• 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.

Time (s)

CBAA

(m/s2)

0 00

Velocity vs. Acceleration Match-Up


V (m/s)

III

III

Time (s)

CB

A

0 00

A

(m/s2)







Graphing Acceleration

• You can use both a speed-versus-time graph and a distance-versus-time graph to analyze the motion of an accelerating object.

- Acceleration

- 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

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

- 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).

- 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.

- 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 adeceleration (slowing down)

- Acceleration

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.







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).

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.

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.

Which of the following is an example of a negative acceleration?

A. A skateboarder taking off from rest to a speed of 5 m/s.

B. A truck going at a constant speed of 65 mph.

C. A bus coming to a stop after a tractor stops in front of it.

D. A car speeding up in the passing lane.

Which of the following is an example of 0 or no acceleration?

A. A bowling ball slowing down when it hits the 10 pins.

B. A car speeding up to pass another vehicle.

C. A bus coming to a stop.

D. 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.

Determine the acceleration of the object from the graph below.

A. 6 m/s/s

B. 2 m/s/s

C. 10 m/s/s

D. 5 m/s/s

If you measure velocity in miles per hour and time in hours, then what would be the units for acceleration?

A. Miles per hour per hour (Miles/h/h or Miles/hr/hr)

B. Miles per hour (mph)

C. Hours (h or hr)

D. Hours squared per mile (hr2/mile)

Determine the acceleration if a roller coaster starts from rest and reaches a speed of 27 m/s in 3 seconds.

A. 9 m/s or 9 mps

B. -81 m/s/s or -81 m/s2

C. 9 m/s/s or 9 m/s2

D. -9 m/s/s or -9 m/s2

A roller coaster goes from a speed of 27 m/s to rest in 3 seconds. What is the rollercoaster’s acceleration?

A. 9 m/s or 9 mps

B. -81 m/s/s or 81 m/s2


D. -9 m/s/s or -9 m/s2

A car is traveling at 20 mph and after 10 seconds, the car is moving at 20 mph. What is its average acceleration?

A. -2 m/s/s or -2 m/s2

B. 2 m/s/s or 2 m/s2


D. It cannot be calculated.

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.

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

Velocity vs. Acceleration Extension• Goal- Create the velocity-time graphs below and describe how you

moved for each one.

• Procedure Help: Switch to Velocity-time graph and use the F2 and upbuttons 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?


IV V VI

0

V

(m/s)

Motion Practice Test1. 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 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 (y-axis) = 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

Main Idea

Detail Detail Detail

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.

In science, acceleration refers to...

Increasing speed Decreasing

speed

Changing

direction

- Acceleration

End of Section:Acceleration

Graphic Organizer

•

Reference

point

Motion

is described

relative to a

Distance

÷ Time

Speed Velocity

is measured by

equals in a given

direction is called

End of Section:Graphic Organizer

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