Simple Physics problem Friction

[flodhi1]

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If a tire with a radius of 0.5 m is rolling with an angular frequency of 30 rad/s, how far will the axle travel
in 2 s?
A) 5 m
B) 10 m
C) 20 m
D) 30 m
The speed of the axle v is related to the tire’s angular frequency by
v = rω
Because the distance d traveled is
d = vt
in 2 s, the axle will travel a distance of
d = v•t = rω•t = (0.5 m)(30 rad/s)(2 s) = 30 m
Thus, D is the best answer.

Units are not canceling out why? I used dimensional analysis and kind of fluked this answer but still pissed because units are not canceling!?

 

[TheRealAngeleno]

30 rad/s x 1 rev/2pi rad = 30/2pi rev/s

30/2pi rev/s x 2pi(0.5m)/1 rev = 15 m/s

15 m/s x 2s = 30m

 

[flodhi1]

30 rad/s x 1 rev/2pi rad = 30/2pi rev/s

30/2pi rev/s x 2pi(0.5m)/1 rev = 15 m/s

15 m/s x 2s = 30m

Great thanks!