- #1
kwixson
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Homework Statement
I have two equations with two unknowns. I know m, F, R, r and I. I need to find a and f.
m = 2
F = 28
R = 0.25
I = 0.0625
r = 0.1875
I know the ultimate answers are [itex]a = 16\frac{1}{3}[/itex] and [itex]f = 4\frac{2}{3}[/itex]
Homework Equations
(1) [itex]Fr-fR=I\frac{a}{R}[/itex]
(2) F+f=ma
The Attempt at a Solution
[itex]Fr-I\frac{a}{R}=fR[/itex]
[itex]f=\frac{Fr}{R}-I\frac{a}{R^2}[/itex]
[itex]I(1+\frac{r}{R})=a(m+\frac{I}{R^2})[/itex]
[itex]a=F(\frac{1+\frac{r}{R}}{m+\frac{I}{R^2}})[/itex]
[itex]28(\frac{1+\frac{0.1875}{0.25}}{2+\frac{0.0625}{0.25^2}})[/itex] = ?
16.333 (Yay!)
I can't get back to f from here. :( Help!
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