Introduction to Part A
Although you may never have given it much thought to your activity the last time you walked from one place to another, you were actually observing some basic physics concepts. Motion is movement from one location to another in a certain amount of time and in a given direction In this activity you will take measurements of your motion and use those measurements to describe and determine relationships moving objects.
Preliminary Questions - To be answered individually.
Within your group, who do you think naturally walks faster? Explain your choice.
* stopwatch
* meterstick
* 2 strips of masking tape
* 5 marking blocks
PROCEDURE
Part A - Walking
One student will walk from strip #1 toward the end of the hallway, another will time and call out each 5 second interval. A third -student will place the marking blocks, in order, next to the walker at each 5 second interval.
Measure and record the distance and the direction from one marker to the next This is the interval DISPLACEMENT.
Repeat steps #2 and #3 for each group member.
Calculate your total distance at the end of each five second interval. Explain how you determined the answers.
Was the total distance for each person the same ? (b) for each of your intervals the same? Explain why.
Calculate your average speed. You must show all your work (K-U-E-S).
Calculate your speed during each five second interval (K-U-E-S). Do you think the average of your interval speeds will equal your average speed calculated in #5? Explain
Calculate your average speed using these interval speeds. Were you correct?
What is the independent variable? dependent variable? Explain each answer.
Construct a distance v. time graph of your walk.
Which group member had the steepest sloped line? the shallowest slope?
What specific measurement does the slope tell you about each member's walk?
Calculate the slope of your graph (K-U-E-S).
Determine the slope of the GA graph. Write down the values Graphical Analysis provides for your slopes. Explain any differences between your calculations above and the GA slopes.
Save your graph as…walk#,
where # = class period. Your teacher needs to check your graph
before you continue.
As you now know when an object changes velocity it accelerates. In this activity you will be measuring the acceleration of a sleek, low friction car traveling down an inclined plane. In this activity you will also be using a timing device called a tape timer to explore the concept of acceleration in more detail. You will be measuring the acceleration of a car as you allow it to roll down an inclined plane at varying angles. The tape timer itself puts a small dot on a strip of paper (ticker tape). The timer makes exactly 60 dots every second, so every 3 dots represents exactly 0.05 seconds and 6 dots represents exactly 0.1 seconds. Since the times are considered exact they will not limit the certainty of your calculations. As the car moves it will pull the tape through the timer and you will be able to measure the displacement of the car’s motion by simply measuring the position of each dot. With this information you can determine the velocity and acceleration of the car’s motion. Finally you will prepare/manipulate graphs of your data to help in visualizing acceleration.
Preliminary Questions - Answer these individually.
Why will the cart roll down the ramp?
Draw what you think the pattern of the dots on the ticker
tape will look like?
1 meterstick scotch tape ballast for cart
1 ~1.0 m ticker tape 1 inclined plane
Part B: Collecting the data
The inclined planes have been pre-set at the assigned angles.
Label one side of the ticker tape at one end - Angle = _____ and your group name.
Thread the labeled end of the ticker tape (label side down, facing the carbon disk) through the timer such that most of the ticker tape is initially draped over the upper end of the inclined plane. Attach this labeled end of the ticker tape to the back of the cart. Be sure the ticker tape has a clear path to and through the timer.
Place the car just below the timer. Turn the timer on and release the car. Be sure to catch the car before it goes flying off the table. Quickly turn the timer off to avoid needless use of the carbon disk.
Part B: Collecting the data
Check the ticker tape to be sure you have visible dots. If not, repeat steps #3 - #5, using the other side of the ticker tape, if necessary.
Remove the ticker tape from the cart.
Lay the ticker tape, flat and straight, on the lab table with label visible. Scotch tape the ticker tape to the table.
Mark the first ‘good’ dot (the “start” point) t = 0 s above the dot and x = 0 m below the dot.
Circle every 3 or 6 dots (this is labeled on your ramp) on the ticker tape. Label each data point with t = appropriate time value (each 0.05 s for every 3 dots and each 0.1 s for every 6 dots) and x = corresponding position, to the nearest 0.01 cm, from the starting point. You do not need to write the units for each data point.
Record your data (time and position) on your data table (the group will need to make one of these at this point).
Completing the spreadsheet
The spreadsheet will do most of the calculations for you, however, you should look at how the spreadsheet does the calculations and see if it makes sense.
Enter your position data into the spreadsheet.
Find the average acceleration over the entire time of travel. Simply average your accelerations for each interval, but leave out the following: The first two accelerations and the last acceleration.
Show/explain your calculation on the same page as your data table and label it as your average acceleration for angle _____.
Save your spreadsheet in your period’s folder as…downhill. Your teacher needs to check your work before you continue
Construct a position v. time graph, with connecting lines, using the Graphical Analysis program.
Describe your graph: (a) the shape and slope, (b) what is happening to the dependent variable v. the independent variable, (c) is the graph showing constant velocity or changing velocity.
Save as...fallpos#.dat, where # = class period.
Determine the slope of your graph by using a best fit line. What does this slope measure? Record this value on your data table. Your teacher needs to check your work before you continue
Construct a velocity v. time graph, with connecting lines, using the Graphical Analysis program.
Describe your graph: (a) the shape and slope, (b) what is happening to the dependent variable v. the independent variable, (c) is the graph showing constant velocity or changing velocity.
Save as...fallvel#.dat, where # = class period.
Determine the slope of your graph by using a best fit line. What does
this slope measure? Record this value on your data table. Your teacher
needs to check your work before you continue
Individual Work
Part A #1-11
Write an evaluation of the lab activity itself (1 paragraph).
Please provide specific and useful information, not just, “I liked my
group….this was a fun lab….”. Also, remember to include supporting evidence
for your evaluation, this is a science class not a daytime talk show.