A hotwheels car with a C rocket engine strapped to it. It ran along a guide line. Here's how our trials and errors eventually granted results. We are tying to measure acceleration, velocity and speed of these cars.
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Step 1: Materials
A toy car (i,.e. Hotwheels, Matchbox), model rocket engine and igniters, pen tube or straw, hot glue gun and glue, zip ties, tape, 16 ft 2x4 piece of wood, 2 metal L brackets with holes drilled through, binder clips, a 12v battery and 10gauge wire . As well as screws and something to screw them in. 5 vernier photogates as well as a computer.
Step 2: The Track
Screw a metal bracket onto each end of the wood. This will be the base of the guide wire. Next, securely tie the wire onto one bracket and run it to the other end. The car will follow this wire.
Step 3: The Car
Take your car and decide where you want your straw/pen tube to go. Maybe through the windows or on the side. It must be parallel to how the car rolls. glue it into place. Then place the rocket onto the car as well. Preferably on the top. Glue, tape and zip tie it down to make sure it doesn't fly away.
Step 4: Ignition
Run the wire through the pen tube. The tube must not be tight on the wire because if it is, there may be too much friction and it could skew the results. Place the car upon the track. Make sure the weight of the car is enough to keep its wheels solidly on the track. Put the igniter into the rocket engine. Place two wires on the end of the igniter and be ready to hook up the wires to a 12v battery. Putting the wires on the battery will ignite the engine, sending the car down the track. The photogates were set up at distances of 10cm, 1.1m, 2.1m, 3.1m, 4.1m to ensure accuracy.
Step 5: Results
Unfortunately, the car didn't register on the photogates. so the whole trial was a waste of time. We got little to no data from the photogates. What had happened was that the zip-tie on top of the car was not tall enough to break the laser for the photogate. We then re-thought our plan. also, the car was straying from the track. The wire was pulled tight enough. Also, the car's inertia had cause the rocket engine to fly off the car after the sudden impact. The force had just been to great for the hot glue to hold.
Step 6: Track 2.
we took a pvc rectangle shaped post, 4x4 and running the length of the wood. we screwd it into the wood. this was to keep the car from straying from the track. next we set up the metal brackets again as well as the wire. we set up the car as previously stated and ran it again for a second time.everything the was the same, except for the pvc, and the wired was pulled much tighter. we ran the car again
Step 7: Results 2
Once again, this ended in tragedy. We had thought the zip tie would have stood straight up during the travel of the car, but it was blown back by the wind. The smoke from the rocket engine also may have block the photogates. The track, however, worked perfectly.
Step 8: Test Number 3
We decided that we needed to test one more time. This time we put 2 pen tubes on either side of the car. The rocket was placed on top of the car and held with hot glue and electrical tape. Instead of trying to use a zip tie to pass through the photogates, we used a 2 inch binder clip. The the silver metal pieces were stood straight up and taped to ensure they passed through the laser of the photogate.
Step 9: Track 3
The third track was set up exactly the same as the first. However, instead of one wire, 2 wires were run down the track to keep stability. The photogates were set up the same too.
Step 10: Results 3
WE FINALLY GOT RESULTS!!! The car ran down the track perfectly and registered at all the photogates. The car had a top instantaneous speed of 19.349845 m/s. Its acceleration was 44.327031m/s/s.