Measuring Velocity with an Air Track

Experiment by Jenny, Jung, and Manuel

Velocity in Uniform Motion

The graph was done in Excel 2010. Notice that all the point are exactly aligned, which means that the air track was perfectly leveled.

Measuring the speed of a glider on an air track

Photos by Francina, Nilsa, Josh, Jamila, Melina, and Jennifer

Accelerated motion

The time of glider passing between photogates is measured with high accuracy (0.001 s). 

The same video in low motion:

Distance in accelerated motion

The air track is elevated (see its right leg in the picture), so the observed motion is accelerated due to gravity. Two photogates allow to measure the time needed to move between them with high accuracy. In our experiment the second photogate was placed each time 10 cm farther to the left (see the data below). 

(Graph by Tim)

Speed in accelerated motion

The glider blocks the photogate passing through. If the glider's flag is 10 cm long and the measured time is 0.214, then the speed of the glider is

v = l / t

v = 0.1 m / 0.2157 s = 0.4636 m/s

Once again, now in slow motion:

Speed in accelerated motion

The photogate measures time of the glider passing through. To calculate its speed, use the length of glider's flag. Moving the photogate farther allows to measure the increasing glider's speed:

v = l / t

l = 10 cm = 0.1 m.

(Graph by Tim)

The graph shows that speed increases at the same rate.

Uniform motion

This setup was used to determine the change in position of the glider in time in the uniform motion. Below there is a graphical representation of the findings.

The graph was done in Excel. Slope of the regression line represents the actual speed of the glider.

(Zuzan's work)