Constant Velocity Lab (Buggy Cars): Experiment No. 2 Submitted By: Sebastian De La Pena-Kenley Period 3: STEM AP Physics 1 September 20, 2019 Constant Velocity Lab (Buggy Cars) Experiment No. 2 I. Objective: To examine the motion of the buggy, in regards to its velocity (the position of the buggy with respect to time) II. Hypothesis: (Write your prediction about the outcome of this experiment.) The more spaghetti strands, the more weight that can be supported. III. Materials: (List the materials used in the experiment.) • • • • Dune Buggy Meter Stick Stopwatch Tape (marking Device IV. Laboratory Set-up: (Take a picture or draw your lab set-up. The caption should describe the set-up) The car moves with a constant velocity in a straight line. We mark its position every 2 seconds with a piece of tape. V. Procedures: (Write the step-by-step procedures of your experiment using your own words. Guideline: Write your procedures in a way that can be followed easily by anyone who would like to repeat your experiment.) Part 1 a) 1. Set the buggy car to a slow speed using the dial. b) 2. Mark the starting point on the floor using a piece of masking tape. (This is the 0 cm point.) When you begin, the front of the car should be at the starting point. c) As the timer reads the time aloud (every 2 seconds) the marker should mark the position of the front of the car with a small piece of masking tape. Take 10 data points. d) Measure the displacement of all the marks from the starting point and record the data in data table 1 and repeat. Part 2 a) b) c) d) Set the buggy car to a fast speed using the dial. Remove the tape marks from part Repeat steps 2-3 from part 1. Measure the displacement of all the marks from the starting point and record the data in data table 2 and repeat. Part 3 a) Remove the tape from part 2. b) You may do TWO of the following with the faster car a. Car starting from a positive position going to the negative position and NOT crossing the origin b. Car starting from a positive position going to the negative position and crossing the origin c. Car starting from a negative position going to the positive position and NOT crossing the origin d. Car starting from a negative going to the positive position and crossing the origin e. A car going from the negative position further going in the negative position c) Record your data in table 3 and repeat. VI. Data TABLE 1 (Slow Speed) Time (s) 0 2 4 6 8 Position 0 80 145 201 268 10 12 14 16 18 20 333 385 451 510 570 631 TABLE 2 (Fast Speed) Time (s) 0 2 4 6 8 10 12 14 16 18 20 Position 0 110 193 285 370 446 531 604 691 781 887 TABLE 3 (Positive to Negative, Crossing Origin) Time (s) Position 0 80 2 6 4 -70 6 -141 8 -206 10 -275 12 -348 14 -436 16 -506 18 -571 20 -637 TABLE 4 (Negative to Positive, Crossing Origin) Time (s) 0 2 4 6 8 10 Position -100 -41 20 88 149 220 12 14 16 18 20 292 378 463 544 625 VII. Analysis: A. Variables: Identify your control variables, independent variable and dependent variables in paragraph form. The control variables in our experiment are things that are kept constant, including: the origin, the method of placing the tape, and the method of measuring the distance between marks. The independent variable in our experiment is the variable that does not rely on any other variable. In this experiment, it is the position of the buggy car. The dependent variable in our experiment is the variable that is reliant on the independent variable. In this experiment, it is time (measured in seconds). B. Graphs: (Graph your data table using Logger Pro, plot your points, draw your line of best fit, determine the equation of the line) TABLE 1: Position (cm) vs. Time (s) 700 y = 32.074x 600 Position (cm) 500 400 300 200 100 0 0 5 10 15 20 25 20 25 Time (s) TABLE 2: Position (cm) vs. Time (s) 1000 900 y = 44.029x 800 Position (cm) 700 600 500 400 300 200 100 0 0 5 10 15 Time (s) TABLE 3: Position (cm) vs. Time (s) 200 100 0 0 5 10 15 20 25 20 25 Position (cm) -100 -200 -300 -400 -500 -600 y = -36.059x + 78.409 -700 Time (s) TABLE 4: Position (cm) vs. Time (s) 700 y = 36.441x - 124.59 600 500 Position (cm) 400 300 200 100 0 0 5 10 15 -100 -200 Time (s) C. Mathematical model (equation of the line): Explain what your equation means. Explain the physical meaning or significance of the slope and the y-intercept. • The slope of the equation refers to the average change in position of the dune buggy every second. • The y-intercept is the position in which the car begins at 0 seconds • The f(x) is the position of the dune buggy, displayed as a function between the slope and the current time, added by the starting position of the buggy D. Errors: (Explain what kind of errors and sources of these errors in your lab experiment.) The method of placing the tape markers could be delayed, and therefore not completely accurate. The process of measuring the marks between pieces of tape could not be completely kept constant, because there was no center point on the piece of tape that we could measure from VIII: Conclusion: In the constant velocity lab, the purpose was to examine the motion of the buggy, in regards to its velocity (the position of the buggy with respect to time). To begin, we measured the positions of two differently-speeded buggy’s (parts 1 and 2). In the third part, we started the buggy at different places in relation to the origin. For the three parts, the numbers that demonstrated position got larger as the time progressed when the buggy was moving further away from the origin, in either direction. A constant speed graph looks like a single line, with one slope, indicating that the car never speeds up nor slows down. IX: Questions Refer to your graphs from part 1 and 2 to answer the following questions. a) Do your data points fall in a somewhat-straight line? a. YES b) What physical quantity is represented by the slope of the line? a. The slope of the equation refers to the average change in position of the dune buggy every second. c) How does the slope of graph 1 and graph 2 compare? What does that really mean? a. The slope for graph 2 is greater than that of graph 1. This means that for every 1 second, the buggy in graph 2 is moving further. d) How would you recognize a graph of an object traveling at a constant velocity? a. I could recognize a graph of an object traveling at a constant velocity because the slope would not change from point to point. Refer to your graph from part 3 to answer the following questions. a) What do you notice about the shape of your graph? (Is it similar to graphs 1 and 2, or different? Explain.) a. The graphs remain linear. The difference between the part 3 graphs is that they have a negative slope, because as time progresses, they go into the negative position. b) How does the slope of the line in graph 3 compare to the slopes of graphs 1 and 2? What does that tell you about the motion of the car? a. The slope in graph 3 is negative, meaning that as time progresses, the car moves in the negative position c) Is the velocity of the car constant or not constant? ___________________ How do you know? a. The velocity of the car is constant. I know this because the car is not speeding up nor slowing down. The Guiding Question: How does the velocity of the car affect its position with respect to time? Our Claim: A car with a higher velocity will reach a further position than the slower car in the same time frame, no matter the origin. Our Evidence: Justification: Our evidence is based on the assumption that both cars maintain a constant velocity and travel the distance in a straight line. We tested in a negative position in a positive velocity, and a positive position with a negative velocity. With this, the car with the higher velocity traveled more distance that the slower car within the same time frame no matter the initial position. Position (cm) TABLE 1: Position (cm) vs. Time (s) 800 600 400 200 0 y = 32.074x 0 10 20 30 Time (s) Position (cm) TABLE 2: Position (cm) vs. Time (s) 1000 y = 44.029x 500 0 0 10 20 30 Time (s) TABLE 3: Position (cm) vs. Time (s) Position (cm) 200 0 -200 0 5 10 15 -400 -600 -800 y = -36.059x + 78.409 Time (s) 20 25 TABLE 4: Position (cm) vs. Time (s) 800 Position (cm) 600 y = 36.441x - 124.59 400 200 0 0 -200 5 10 15 Time (s) 20 25