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Jar9284
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Homework Statement
You switch a food blender from its high to its low setting; the blade speed drops from 3100 rpm to 1300 rpm in 2.1 s. How many revolutions does it make during this time?
Homework Equations
[tex]\omega[/tex]i = [tex]\frac{3100 rpm * (2 * pi)}{60}[/tex] = 324.6 rad/sec
[tex]\omega[/tex]f = [tex]\frac{1300 rpm * (2 * pi)}{60}[/tex] = 136.1 rad/sec
[tex]\omega[/tex]f = [tex]\omega[/tex]i + [tex]\alpha[/tex]t
[tex]\omega[/tex]f[tex]^{2}[/tex] = [tex]\omega[/tex]i[tex]^{2}[/tex] + 2[tex]\alpha[/tex]([tex]\Delta[/tex][tex]\Theta[/tex])
The Attempt at a Solution
136.1 = 324.6 + 2.1 [tex]\alpha[/tex]
[tex]\alpha[/tex] = 89.8 rad/sec[tex]^{2}[/tex]
136.1[tex]^{2}[/tex] = 324.4[tex]^{2}[/tex] + 2 * 89 ([tex]\Delta[/tex][tex]\Theta[/tex])
([tex]\Delta[/tex][tex]\Theta[/tex]) = 482.8 rad / (2 * pi) = 76.8 rev
Want to make sure if this is correct.