I need to design a car that stops on a dime! (HMWK PHYSICS)?

Question

for this car it will come off a ramp and will have to travel 3 meters and stop on a mark (where a dime is placed).
i have to design this car! It can't have any source of power, except the momentum gained from the ramp. It could have some form of breaking system!

LOOKING FOR SUGGESTIONS

you are not allowed to have a strong breking system like from a rc car!

Answer 1

Have it drop an anchor at the top of the ramp with a string just long enough to reach the dime.

Choose the weight and friction so it slows down and stops at the dime.

Put a driver in the car and give him instructions.

Put a computer in the car with sensors. Use the motion of the car to generate the power.

Ask a bunch of people to think up answers for you.

Answer 2

Best way is to have a wall built on top of the dime.

Second choice is to have a 3 m long wire that is attached to the base of the ramp (or at the top of the ramp, but then it would have to be 3 m + length of the ramp long). The car would come to a dead stop at the end of its leash.

If you are not allowed to creatively cheat in this way, you can have the 3 m + wire spool off from a bobbin inside the car and wrap around the axle of the car, when the wire is spent, the axle would be prevented from spinning anymore, stopping the car -- the problem here is that it may skid a little unless you have very good traction with the wheels. This is simple and fool proof.

If this is a race and you need to be fast, you have to make the car as heavy as allowed, as it maximizes the energy. Remember: gravity pulls equally on everything, so all cars would essentially go the same speed at the base of the ramp, except for the aerodynamic drag -- function of size and shape -- and friction losses -- function of the weight and wheel lubrication. Once you are at the bottom of the ramp, the only factor that slows down the car are the aerodynamic drag and the wheel friction, and the only thing that keeps it going is the momentum, and you need as much momentum as possible to reduce the slow down effect.
Braking is a function of the friction of the wheel on the ground and the weight above it, so technically, braking an heavy car and a light car would take the same distance, save for the heat absorbtion capacity of the brake system, which should not be an issue for small cars like that.

Answer 3

Make the car lightweight. The less momentum it has the quicker it will stop. Also use rubber tires.

One clever thing I've seen done is someone had their wheels on a long screw. They would wind wheels back exactly 3m so that as soon as the car traveled the 3m the screws would lock, locking the tires and stopping the car. This car was quite fast and very accurate in stopping.

The experiment you are trying to do is a classic (just like the egg drop). You should try to think up clever solutions yourself. The one I just mentioned made it to the national championship and may have actually won that year.

Answer 4

rc car brakes =D