## Rubber Band CarsBy Will Macgrath and jack norton

Formulas

Car #1

Distance: 2 feet

Successes: We learned the basics of how to build a rubber band car

Improvements that needed to be made: reduce drag on the ground, make a smaller catch, reduce friction

Car #2

Distance: 7 feet

Modifications: We attached wooden sticks to the bottom of the car. This was to reduce the drag and to help the back glide. We also attached sticks as supports so the car didn't fold in on itself.

Successes: The car had a quick start but quickly slows down

Improvements that needed to be made: we needed to make the wheels wobble less and the rubber band needed to be able to wind up more.

Car #3

Distance: 12 feet

Modifications: The body of the car is much smaller and we left a lot of room in the middle for the rubber band to wrap around. The diamond shape helped the car to withstand pressure and to not fold in.

Successes: The wind-up and the rubber band was able to be stretched and loaded quickly and easily.

Improvements that needed to be made: The wheels needed to be a little more secure. Also, we needed to have something touching the ground. After a first successful attempt the car stopped moving forward. The body spun around and the wheels stayed in place.

Final car #4

Distance: 22 feet

Modifications: We added a long stick and completely changed the body shape. The body was stiff and supported by the wooden sticks. The rubber band was set far back to be able to stretch.

Success: This car went the farthest out of all of ours and had a quick acceleration.

Improvements that needed to be made: The car went forward then quickly turned back around and came back. The wheels also needed to be better aligned.

Kinetic and Potential Energy: Kinetic and Potential Energy is the energy before an object moves and the energy when it moves. The energy turns from potential to Kinetic when you are winding up the rubber band. The more you wind the rubber band up the more potential energy you have which transitions into Kinetic energy.

The Formulas for finding the velocity and acceleration for the cars are a=dv/dt which are acceleration equals distance velocity divided by distance time. The acceleration for the car was 0.4 mph the second acceleration is found using the same method. The acceleration for the peak speed was .57 mph a slight improvement.

Calculating Velocity

Using the formulas we were able to calculate that our best rubber band car went at its fastest .95 mph. The formula that I used was change in time position by change in time. The car went 4.75 meters in 5 seconds so when you divide the two it comes out to .95 miles per hour.

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