- #1

neongoats

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## Homework Statement

Two bicycle tires are set rolling with the same initial speed of 3.30m/s along a long, straight road, and the distance each travels before its speed is reduced by half is measured. One tire is inflated to a pressure of 40 psi and goes a distance of 17.3m ; the other is at 105 psi and goes a distance of 93.0m . Assume that the net horizontal force is due to rolling friction only and take the free-fall acceleration to be g = 9.80m/s2

What is the coefficient of rolling friction μr for the tire under low pressure?

## Homework Equations

Fx=ma

Fx=μn

n=mg

v2=v02+2a(x−x0)

## The Attempt at a Solution

First I solved for the acceleration:

1.65^2 = 3.3^2 + 2a(17.3)

a= -.24

Then I set Fx=ma and Fx=μn to be equal, and substituted n=mg in for n

ma=μmg

The masses cancel out so I get

a=μg

I tried solving for this

-.24=u(9.8)

and got -.024, but this answer was incorrect.

I feel good about this process but don't know I'm doing wrong? I found another question exactly like this on here but when I tried to do the calculations for acceleration I kept getting a different number, so I don't know if that's where my problem lies but if so I don't understand how my math is wrong.