Does adding weight/mass in a car make it roll down a hill faster

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Does adding weight/mass in a car make it roll down a hill faster

[From: ] [author: ] [Date: 11-08-23] [Hit: ]

______the air resistance increases with the square of the velocity. the resistance from the bearings stays pretty constant throughout the whole ordeal. this means that even though the bearing resistance is larger than the drag at first, the air resistance will rapidly overtake it and dominate the determination / calculations of the cars speeds. so it does not pay to fork out worry and money into progressively better and better bearings._____if you make the wheels out of light plastics and make them skinny (the more mass you can shave off of those wheels the better,......

_____ you can make the car faster by making the body form 1. more sleek and 2. more narrow (less cross sectional area as seen looking at the face of the car) AND or reducing bearing frictions.
______the air resistance increases with the square of the velocity. the resistance from the bearings stays pretty constant throughout the whole ordeal. this means that even though the bearing resistance is larger than the drag at first, the air resistance will rapidly overtake it and dominate the determination / calculations of the car's speeds. so it does not pay to fork out worry and money into progressively better and better bearings.
_____if you make the wheels out of light plastics and make them skinny (the more mass you can shave off of those wheels the better, drill holes in them), and lots of mass in the body concentrated as close to the center of gravity as is possible.. the act of optimizing all of those together is the act of making a faster pinewood derby car. but keep in mind the maximum accelerations felt by the car will always be less than that of the car in a vacuum. little weights make a big difference, but there might not be that much difference between a plutonium brick and a sun's mass for a car weight. weight in the car body is good, but weight in the wheels themselves is very bad.
:)

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Because we live on Earth and not some magical planet that's a vacuum and frictionless, adding mass does increase speed because the amount of friction created by adding mass is offset by additional gravitational force created by the extra weight

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m +
W +
N +
f +
R +

a = (W - f - R)/m = g - (f+R)/m

a + = (W+ - f+ - R+)/m+ = g - (f+ + R+)/m+

It must be that (f+ + R+)/m+ < (f+R)/m or m/m+ < (f+R)/(f+ + R+)

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The key in those little cars is the wheel bearings. Your car probably had the best bearings.

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