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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 V_{i}, V_{f} 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 V_{i}, V_{f} 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:

Insert both graphs with your work in your notebook.

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

Calculate % errors.

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