Constant Velocity of a Train
:  Measure distance and time of moving object; graphically analyze its motion.
Equipment:  60 Hz timer,  train

Lehigh Valley

1.  Attach the paper tape to the train, then thread it through the timer beneath the carbon paper.
2.  Turn the timer on and run the train down the track for 1-3 s or 1-2 m.
3.  Record the markings as described for distance (cm) and time (0.1 s) on a data table.  Avoid the beginning and end of the tape where the train may be accelerating/decelerating.
4.  Plot an accurate distance vs. time graph.  Calculate the slope.
5.  Sketch a simple velocity vs. time graph of the train’s motion.

1.  Compare the average speed of the train [total distance/total time] with the slope of the d-t graph.
2.  Write an equation relating v, d, and t.
3.  Calculate the area under the sketched v-t line.  Compare with the total distance you measured.
4.  Using the speed of the train determined from your slope, calculate:
     a)  the distance (in meters) the train would travel in 5.0 min.
     b)  the time required to travel 100 m.
5.  Summary.

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