UNIFORM MOTION LAB HONORS

Name: ______

Partners: ______

______

Purpose:

Equipment:

Procedure:

  1. Follow your instructor's directions to calibrate the strip timers. Save the tape. In your lab reports, describe how the timer calibration is done.
  2. Use the strip timers to record the motion of two carts as they roll freely across the floor. Give them a push, let them roll, and catch them on the other side. One should be fast and the other slow. Label the beginning of the tape as either fast or slow.
  3. Place both tapes on a table, and on each, measure the distance the dots are from the starting point and record these distances in a data table. Measure the dots until the cart is no longer moving freely, but do not exceed 100 dots on each tape.
  4. In Excel, make a distance vs. time graph, placing both trials on the same graph. Distance is in “cm” and time in “number of dots.”
  5. Draw best-fit lines for the major straight section for each set of data.
  6. Calculate the slope of each best-fit line. Be sure to show your slope calculations on the graph paper so that it is easy to see exactly which points you used and how you did the calculation.
  7. Convert your units of time from “numbers-of-dots” to “seconds” using your timer calibration. Do this conversion only when doing slope calculations.

Questions, Analysis & Conclusions:

  1. Tape the paper tapes next to each other on the table. Compare the spacing of the dots for when they were rolling freely across the table. Which trial had a greater spacing between dots and what does this mean?
  2. What is the motion of the cart if the best-fit line is straight? What does a steep best-fit line mean? What does a shallow best-fit line mean? What does a flat best-fit line mean?
  3. What are your slope values for the trials and what do these values tell us about the carts?
  4. In places where the best-fit line on the graph is a curve, what does a curved line of data mean? What is happening if the curve of the best-fit line is upward (it is becoming steeper)? What if it is curving downward (becoming flatter)?
  5. Select a point on a curved section of the plot of either of your graphs, draw a tangent at this point, and calculate the slope of the tangent. Again, show all calculations clearly on the graph paper and convert the units of time. What does this slope number tell us?
  6. Write an equation for the line for each straight-line graph (estimate the values for the y-intercepts). Try to explain what these equations represent and to which Physics formula they correspond.

Lab Report:

·  Be sure to clearly describe the timer calibration method.

·  Make sure graphs are completely labeled.

·  Make sure slope calculations contain units.

·  Answer the questions in complete sentences, and make them long enough to support your conclusions.