Group4.1-4-EB

=__GROUP 4, PERIOD 4: Chris Hallowell, Richie Johnson, Tom McCullough, Bret Pontillo__=

Lab 3: What is the acceleration of a falling body?
Chris and Richie

**Bret and Tom Lab 3:**

** LAB 2: A CRASH COURSE IN VELOCITY **
** DUE: 9/27 ** ** Materials: Constant Motion Vehicle, Tape measure and/or metersticks, Masking Tape (about 30 cm/group), spark timer, spark tape ** ** Objectives: **

PURPOSE: In this experiment, we are looking to prove “catching up” and “colliding” equations accurate through a visual demonstration and collecting data.

HYPOTHESES: We believe that our visual demonstration will our catching up equation correct because of accurate velocities of the two CMVs. We also believe that the visual demonstration will prove that, in a colliding problem, the collision will always happen closer to the side where the slower CMV started. good

PROCEDURE FOR OBJECTIVE 1:

1- Obtain two strips of ticker-tape each one meter long

2- Load one strip of ticker-tape into the ticker-tape timer

3- Attach the front of the strip of ticker-tape to the slowcar using a small piece of masking tape

4- Set the ticker-tape timer to 10hz and then turn it on

5- Turn on the car with the tape attached to it and let run until it has pulled the strip of ticker-tape completely through the ticker-tape timer

6- Record the information on the strip of ticker-tape

7- Repeat steps 1-6 for the fast car

DATA FOR OBJECTIVE 1:


 * Slow Car Time (s) || Slow Car Distance (m) || Fast Car Time (s) || Fast Car Distance(m) ||
 * 0 || 0 || 0 || 0 ||
 * 1 || 0.0890 || 0.1 || 0.0179 ||
 * 2 || 0.1925 || 0.2 || 0.0440 ||
 * 3 || 0.3005 || 0.3 || 0.0728 ||
 * 4 || 0.409 || 0.4 || 0.1035 ||
 * 5 || 0.5163 || 0.5 || 0.1350 ||
 * 6 || 0.6308 || 0.6 || 0.1676 ||
 * 7 || 0.7389 || 0.7 || 0.2011 ||
 * 8 || 0.851 || 0.8 || 0.2351 ||
 * 9 || 0.9639 || 0.9 || 0.2702 ||
 * ||  || 1.0 || 0.3036 ||
 * ||  || 1.1 || 0.3291 ||
 * ||  || 1.2 || 0.3723 ||
 * ||  || 1.3 || 0.4079 ||
 * ||  || 1.4 || 0.4430 ||
 * ||  || 1.5 || 0.4787 ||
 * ||  || 1.6 || 0.5129 ||
 * ||  || 1.7 || 0.5480 ||
 * ||  || 1.8 || 0.5845 ||
 * ||  || 1.9 || 0.6209 ||
 * ||  || 2.0 || 0.6570 ||
 * ||  || 2.1 || 0.6922 ||
 * ||  || 2.2 || 0.7296 ||
 * ||  || 2.3 || 0.7621 ||
 * ||  || 2.4 || 0.7970 ||
 * ||  || 2.5 || 0.8341 ||
 * ||  || 2.6 || 0.8692 ||
 * ||  || 2.7 || 0.9091 ||
 * ||  || 2.8 || 0.9424 ||
 * ||  || 2.9 || 0.9777 ||
 * ||  || 3.0 || 1.0134 ||

GRAPH FOR OBJECTIVE 1:



CALCULATIONS FOR OBJECTIVE 1:

Not necessary, just use slope from best fit equation

PROCEDURE FOR OBJECTIVE 2a:

1- Measure out six meters with measuring tape and lay it in a straight line on the ground

2- Line up the front of the slow car with one end of the tape and the front of fast car with the other end of the tape (make sure they are traveling in opposite directions towards each-other)

3- Switch each car on at the same time and observe and mark where the two collided on the measuring tape

4- Record where they collided

5- Repeat steps 1-4 for at least 6 trials

CALCULATIONS 2a:

DATA FOR OBJECTIVE 2a and 2b:

PROCEDURE FOR OBJECTIVE 2b:

1- Use a meter stick to measure out 1 meter on the floor and a measuring tape to measure out 3 meters (total of four meters measured out on the ground)

2- Line up the front of the fast car at one end of the meter stick and the back of the slow car at the other end of the meter stick (make sure they are traveling in the same direction and that the fast car is behind the slow car)

3- Turn on both cars at the same time and record where the front of the fast car met the back of the slow car on the measuring tape

4- Repeat steps 1-3 for at least 6 trials

CALCULATIONS 2b:

nice presentation of calcs and data.

DISCUSSION QUESTIONS: > The slope of the position time graph is equivalent to the average velocity because the average velocity is equal to the change is in displacement over elapsed time, which is what the graph illustrates “As slope goes, so goes velocity” > > The y-intercept is allowed to equal zero. It can because according to time, there is no negative position. Since the object begins at rest as we start the spark timer, it would not have a distance yet. The coordinates would then be at (0,0). > > The R2 value helps determine the preciseness and accuracy of your data on your graph. It helps determine how closely the data matches in a linear relationship. You want the R2 value to be a higher percentage. A percentage that is lower means that your data did not match the resulting line well. The R2 value should be higher then 97%. If the value is below 97% then you should go back and review the accuracy of your recorded data. > If both cars had equal speed then they would travel the same distance over the same time period. If the cars were traveling same rate in the collision problem they would pass each other at the same time. In the collision problem, the cars were 600 centimeters apart. They would meet in the middle, 300 centimeters from where they started. This of course is excluding human error. For this, human error consists of not starting the cars at the exact same time or not putting them parallel to each other. In this instance since the cars would have the exact same speed, the catching up problem would not work. The car starting 100 centimeters behind the other would not be able to pass the car starting 100 centimeters ahead because of they are going the same speed > Where the two lines cross is where the two cars at the same place at the same time. The distance in meters, represents the distance away from the other car. > i > Once again where the two lines cross is where the cars are at the same place and at the same distance. Also, this distance represents the full distance traveled. > > > > > There no where to find the points in the velocity time graph because the lines do not intersect in the catching up situation. Since there the car's speeds are constant, there would be zero slope in the velocity time graph. So the velocity time graph would not tell us anything because both cars would have horizontal slopes after the accelerating to constant speed.
 * 1) Why is the slope of the position-time graph equivalent to average velocity?
 * 1) Why was it okay to set the y-intercept equal to zero?
 * 1) What is the meaning of the R2 value?
 * 1) Where would the cars meet if their speeds were exactly equal?
 * 1) Sketch position-time graphs to represent the catching up and crashing situations. Show the point where they are at the same place at the same time.
 * 1) Sketch velocity-time graphs to represent the catching up situation. Is there any way to find the points when they are at the same place at the same time?

CONCLUSION: After performing the three experiments, we can conclude that our hypotheses were correct. After we collected our data from both the collision and catching up demonstrations, we then found the theoretical solutions to the two equations by using the velocities we established earlier. After obtaining our theoretical answers, we then set up percent error problems for both the collision and catching up problems. Our percent error for the collision problem was only .9%, which means we were very successful. Our percent error for the catching up problem was 23.66%, which means we could have been a little more precise. One of the main forms of error in both the collision and catching up problems was human error. There were two main cases of human error. The first was our inability to start both CMVs at the same exact time for every trial. We definitely were very close every trail, but it is very unlikely that we were perfect every time. The second form of human error was our inability to tell the exact spot where the CMVs collided and where the fast CMV passed the slow CMV. We had to use our eyes to try to tell the exact spot of where the intersection occurred. This did not greatly affect our results but it definitely allowed for some variation in the results of our trials. In order to stop these types of error from happening, we would have to use more high-tech CMVs that would be able to start at the exact same time. Another way to improve this lab’s accuracy would be to use a computer program that would give us exact measurements and take out all the human error. The concepts used in this lab are important to know because we are using them while driving everyday. We are constantly thinking how much faster we have to go to pass someone on the highway, and how fast we have to go to make a turn at an intersection before the other car reaches the intersection as well.

DUE: 9/20/10
**OBJECTIVE: What are the different types of motion? What is the best way to represent motion?**

MATERIALS: Motion Detector and USB link, spark timer and ticker tape.
HYPOTHESIS: Webelieve that the graphs from DataStudio will provide the best way to represent motion because of the exact measurements you can obtain, as well as the ability to compare measurements to time.

PROCEDURE - MOTION DETECTOR: 1. Set Up a motion detector to be used in DataStudio.

2. Then set up DataStudio to record acceleration, position, and velocity, to be placed in graphs. a. To make sure all trials have the same constants use a laptop case in front of your knees.

3. Run each trial a. No motion: hold the laptop case in front of motion detector and stand motionless. b. Increasing Speed Toward: Stand 3.3 m away from the motion detector and move slowly at first but begin to accelerate on your way towards the detector. c. Increasing Speed Away: Starting close to the motion detector and moving back slowly at first then accelerate faster d. Constant Speed toward: Move towards the Motion detector staying the same speed. e. Constant Speed Away: Move away from the motion detector staying at same speed. f. Decreasing Speed Towards: Move towards the motion detector first fast then reducing speed. g. Decreasing Speed Away: Move away from the motion detector first fast then reducing speed.

4. Use graphs created from DataStudio to analyze data.

PROCEDURE - TICKER TAPE: 1. Place a piece of ticker tape (approximately .3 meters) into the spark timer.

2. Run each possible trial (cannot run "towards" trials with a spark timer) a. No motion: don’t move the strip of ticker tape b. Increasing Speed Away: Pulling slowly at first then gradually increasing the rate c. Constant Speed Away: Pull tape through at the same rate. d. Decreasing Speed Away: Pulling fast at first then gradually slowing down the rate to pull.

3. Record and analyze the data.

DATA TABLE:

Compare: Qualitative Representations of Motion Mostly good data, although a-t graphs are a bit messy!

ANALYSIS AND DATA INTERPRETATION QUESTIONS:

Many of your responses are incorrect or too vague to be clear. When there is no motion, both the acceleration and the velocity are equal to zero When there is not motion, the ticker only plots one point on the strip of tape. When there is no motion, the position graph forms a straight line with a slope of zero When there is no motion, the velocity graph forms a straight line with a slope of zero When there is no motion, the velocity graph forms a straight line with a slope of zero
 * 1) How can you tell that there is no motion on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

When motion is steady, the arrows have equal lengths and there is no acceleration. When motion is steady, the distance between the marks on the tape is equal. When motion is steady, the points on the graph have a constant slope. When motion is steady, the points on the graph have a slope of zero because the velocity is constant. When motion is steady, the points on the graph have a slope of zero because there is no acceleration.
 * 1) How can you tell that your motion is steady on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

When motion is going faster or slower, the arrows representing the velocity will wither become larger or smaller. When motion is going faster or slower, the dots either become further apart or closer together. When motion is going faster or slower, the slope of the dots on the graph either increases or decreases. When motion is going faster or slower, the dots on the graph are either far away from the origin or close to the origin. When motion is going faster or slower, the dots on the graph are either far away from the origin or close to the origin. X
 * 1) How can you tell that your motion is fast vs. slow on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

When direction changes, the velocity and acceleration arrows point in the opposite direction of where they originally pointed. When direction changes, the dots on the tape will darken because it places more dots over the dots that were already made. When direction changes, the slope of the dots will become opposite of what it was originally (+ becomes – and – becomes +). When direction changes, the dots will move to the other side of the axis. When direction changes, the slope of the dots will stay constant except at the point where the directional change is made. This is not correct.
 * 1) How can you tell that you changed direction on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

When motion is increasing, the velocity and acceleration arrows point in the same direction. (right) When motion is increasing, the spaces between the dots on the tape become greater and greater. When motion is increasing, the slope of the dots on the graph increases at a fast rate When motion is increasing, the slope of the dots on the graph increases at a fast rate This is not clear. When motion is increasing, the slope of the dots on the graph increases at a fast rate This is not true.
 * 1) How can you tell that your motion is increasing on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

When motion is decreasing, the velocity and acceleration arrows point in the same direction. (left) When motion is decreasing, the spaces between the dots on the tape become smaller and smaller. When motion is decreasing, the slope of the dots on the graph decreases When motion is decreasing, the slope of the dots on the graph decreases. This is not clear. When motion is decreasing, the slope of the dots on the graph decreases. This is not true.
 * 1) How can you tell that your motion is decreasing on a…
 * 2) Motion diagram
 * 1) Ticker tape diagram
 * 1) position vs. time graph
 * 1) velocity vs. time graph
 * 1) acceleration vs. time graph

DISCUSSION QUESTIONS: 1. What are the advantages of representing motion using a…  1. Motion diagram 1. We are able to see exactly whether velocity and acceleration are increasing or decreasing and we are able to see their direction of motion. 2. Ticker tape diagram 1. We are able to see whether the tape is increasing, decreasing, or staying constant in velocity. 3. position vs. time graph 1. We are able to see how fast something is changing its position over time. 4. velocity vs. time graph 1. We are able to see exact measurements of how fast something’s velocity is changing over time. 5. acceleration vs. time graph 1. We are able to see exact measurements of how fast something’s acceleration is changing over time. 2. What are the disadvantages of representing motion using a…  1. Motion diagram 1. When using a motion diagram, we are not able to see exact measurements of velocity or acceleration. We are also not able to see the time of the experiment. 2. Ticker tape diagram 1. We are not able to see the exact measurements of velocity or acceleration. We are also not able to see whether the speed is increasing/decreasing towards or away. 3. position vs. time graph 1. We are not able to tell the acceleration of the object using this graph. 4. velocity vs. time graph 1. We are not able to tell the exact position of the object over time. 5. acceleration vs. time graph 1. This graph does not allow us to see the exact change in position of the object over time. 3. Define the following: 1. No motion 1. When an object does not change its position, therefore no velocity or acceleration is present. 2. Constant speed 1. When an object stays at a constant velocity and the acceleration remains at 0. 3. Increasing speed 1. When an object’s velocity and acceleration are going in the same direction. 4. Decreasing speed 1. When an object’s velocity and acceleration are going in opposite directions.

CONCLUSION:

After performing our lab and analyzing our data, we were able to justify our hypothesis. The graphs that we obtained from using the motion detector and DataStudio program proved to be the best way to represent the types of motion involved. In all three of the graphs, we were able to obtain exact measurements and compare them to time elapsed. This ability to compare position, velocity, and acceleration to time was very useful in analyzing the data. These graphs were better at representing the motion than the ticker tape and motion diagrams because the ticker tape and motion diagrams did not show exact measurements and time in the results.

The error that might have caused some inaccuracy in our experiment was two cases of human error. The first was our inability to walk without pausing. In order to try to stop this from happening, we placed a laptop case in front of our legs and tried to “glide” instead of our usual walk. The second case of human error was our inability to keep a consistent acceleration when increasing and decreasing speed. Need to address how to fix error if possible, but otherwise very well-stated.