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Inquiry: Air Track Physics

Purpose: To validate Newton's Second Law.

Procedure:

Air tracks are devices for floating small carriages on an almost frictionless film of air along a metal track. We will be using the Photo Gate Timing mode in the Data Studio Program. In this Inquiry we have a 2.0 cm flag traveling through 2 photo gates that are 70.0 cm apart. Click the Setup button and check mark only "velocity in gate" and "time between gates".

Constant Mass - Varying Force:

  • Load 12 washers in the carriage and 2 washers on the end of the string.

  • Mass everything and record the constant mass in your notebook.

  • Mass the washers on the end and convert to force.

  • Start the blower and let the air fill the track, click Start on the computer, release the carriage and then click stop.

  • Record Vi, Vf and total time. Then calculate the acceleration rate.

  • For the second run, repeat the procedure with 4 washers on the end of the string by transferring 2 washers from the carriage. This will change the force but keep the entire mass constant.

  • Again, mass the washers on the end and convert to force.

  • Repeat the procedure until you have made five runs each time adding 2 more washers to the end of the string from the carriage and record your data.

  • Graph force on the y-axis and acceleration on the x-axis and use a trendline to determine the R-value and the slope of the line. Determine % error between the slope and the constant mass.

Constant Force - Varying Mass:

  • Use the same procedure as in part I, but this time keep 10 washers on the end of the string while changing the mass in the carriage.

  • Record the constant force in your notebook. Also record Vi, Vf and total time. Then calculate the acceleration rate.

  • Start with 10 lead squares in the carriage and remove 2 squares each time to reduce the mass in the carriage.

  • Mass everything for your first trial.

  • On each trial mass the two lead squares and subtract them from the mass.

  • Graph acceleration on the y-axis and 1/mass on the x-axis and use a trendline to determine the R-value and the slope of the line. Determine % error between the slope and the constant force.

Inquiry Questions:

  1. Insert both graphs with your work in your notebook.

  2. Explain why we graphed them this way and how well they proved Newton's second law.

  3. Calculate % errors.

  4. A 230 Newton object is pushed along a frictionless track with a force of 120 Newtons. What is the acceleration rate of the object?