Rotational kinematics

  • #1
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Homework Statement


A wheel of diameter 45.0 cm starts from rest and rotates with a constant angular acceleration of 2.50 rad/s2 . At the instant the wheel has completed its second revolution, compute the radial acceleration of a point on the rim in two ways.

1 Using the relationship aredial2r.

2 From the relationship aredial=v2/r.

Homework Equations


v=ωr
rotational kinematics
aredial2r
aredial=v2/r.


The Attempt at a Solution



α= 2.5
it says second rotation so θ= 2π*2 = 12.57

θ = ωt + ½ α t2
12.57 = ½ 2.5 t2
t= 3.171

ω = ω + α t
ω = 2.5 (3.171)
ω = 7.927

aredial2r
a = 7.9272 * 22.5 = 1413.716694

2 should be the same answer since the equations are equal
why is my answer wrong?
 

Answers and Replies

  • #2
PeroK
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why is my answer wrong?
Is the diameter of the wheel ##45m## or ##45cm##?
 
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  • #3
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Is the diameter of the wheel ##45m## or ##45cm##?
got it, there was my mistake, thank you
 

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