I think your adviser is leading you to learning how forces change on an inclined plane which is a good thing to learn. I’m trying to help my 11th grade daughter with the same thing right now and I know how difficult it is. I have to agree with some of the above, if you want to do a good job measuring air drag based on different shapes, then a wind tunnel is the way to go if you can get to one. If a near by university has one, it’s a great way to see and learn way more than your experiment will teach you. If none is available I’d suggest the following:
Build a simple wind tunnel. I’d get a refrigerator box and with duct tape build a square tunnel about one foot square and 4 feet long. Put a large box fan at one end. Cut out trapezoid shaped pieces of card board and tape them together to match the fan size down to the tunnel. The trapezoid section is called a plenum and the tunnel is called a duct. Build a small table in the middle of the tunnel that you can place your car on. Adding a door you can close will help. When the fan is on, a FORCE will be exerted on the shape. You can measure this force by tying a string to the car, running the string over a pulley and seeing how much weight can be placed on the end of string to balance the force of air. This would be when the car does not move. see figure 1 in this link for an idea on how this might be set up.
http://en.wikibooks.org/wiki/How_To_Build_a_Pinewood_Derby_Car/Physics
skip all the stuff before it as it’s pretty complex, just get the idea from the drawing.
To be accurate, measure the friction of the car wheels by this method with the fan off, subtract that from what you get with the fan on. Don’t wory about measuring the air speed, you’re looking for the effect of shape on drag. In this case you want the air speed to be the same for each measurement.
If you are still thinking of measuring acceleration using a track, here is what I’d suggest.
You’ll need a cam corder that can display time to at least a tenth of a second or video editing software that shows time.
Mark off the track with clearly visible stickers every foot. Video record runs of different shaped cars. Determine the time it takes to go through each one foot section. Calculate the average speed in each section, speed = distance/time
plot the speed against time. If you do this you should see a straight line with different slopes for each shape. ACCELERATION is the change in SPEED over a period of time.
or (Velocity at time2 – Velocity at time1)/ (time 2— time1)
Acceleration will also be the slope of the line.
CAREFUL this is getting you dangerously close to Calculus! Once you go down that road, wonderful things are learned!