Posted by **help** on Wednesday, January 27, 2010 at 6:09pm.

A merry-go-round accelerates from est at .870 rad/sec^2. When the merry-go-round has made 4 complete revolutions, how much time has elapsed since the merry-go round started?

What is the angular velocity of the merry-go round?

Could someone help, please

- Physics -
**Damon**, Wednesday, January 27, 2010 at 6:13pm
a = angular acceleration

w = a t = angular velocity

theta = (1/2) a t^2 = radians turned total from rest

in this case thetas = 2pi * 4 = 8 pi radians

so

(1/2) a t^2 = 8 pi

you know a, get t and then w

- Physics -
**jessica**, Wednesday, January 27, 2010 at 6:25pm
to double check , the correct answer for time is 7.60 sec? and w is 6.61 rad/s?

- Physics -
**Damon**, Wednesday, January 27, 2010 at 6:37pm
(.87/2)t^2 = 8 pi

t = 7.599 yes 7.6

w = .87*7.6 = 6.61 yes

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