
HandsOnPhysics MECHANICS

Core Project

 Analysis 

Speed
Testing the Aircart's speed
involves two variables, the distance traveled and the time required to travel
that distance. If you set the distance (say, to one meter), then distance
(d) is the independent variable, and you must measure
time (t) which would be the dependent
variable in this case. If, on the other hand, you choose the pick a time
(say, three seconds) then time is the independent variable and you must
measure distance, the dependent variable. In this case distance depends
on the time you choose.
After making several "runs" to get a few measurements, calculate
the average time or distance.
( Average Measurement = sum of measurements / number of measurements).
Calculating the average speed
is easy, it's just the ratio of distance to time, d / t. However,
the final speed, that is, the speed at the end of the interval, is bigger
than the average speed because the Aircart is speeding up. If the Aircart
starts it's run from rest (zero speed), then the final speed is twice the
average.
Double the time or distance and measure you aircart's average speed again.
How "fast" is your aircart?
You could setup a straight test track three meters long to evaluate your AirCart.
Mark the start, 0.5 meter, 1.5 meters, and 3 meters. Use the lap timer to measure the time to travel
each of the three sections.
Suggestions for Analyzing Your Aircart
 Calculate its average speed over the halfmeter (starting from rest).
 Calculate its average speed over middle onemeter (after it has sped up for half a meter).
 Calculate its average speed over last 1.5 meters.
 Calculate the acceleration over the first half meter of the track.
(Over the first meter these aircarts have a nearly constant acceleration.)
 The aircart's initial speed was zero, and you can calculate other three speeds,
That means you can also calculate three accelerations.
Click here for more information about calculating speeds.
Questions
Does your AirCart have a constant acceleration over the entire trip?
Does your AirCart have a constant speed after three meters?
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