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29 Oct 2009 02:12:33 IST

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The graph to the left shows the angular velocity of a rotating wheel as a function of time. a

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The graph to the left shows the angular velocity of a rotating wheel as a function of time.a) What is the angular displacement of the wheel at t = 1.2 sec?b) What is the angular displacement of the wheel at t= 3.6 sec?Image:http://img140.imageshack.us/img140/513/showme.jpg

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piyush jain

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Joined: 1 Jun 2009

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29 Oct 2009 02:21:14 IST

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hiiiiii

Let d be the radians, v be the angular velocity, and a the angular acceleration.

Given the equation
v = v1 + a•t

From the graph you know that v1=-9
You also know that at t=3 ,v=0 so...

0 = -9 + a•3
know you can solve for a

Another way would have been to note that
a=dv/dt
and you could have just calculated the slope of the line in some way.

Now that you have a you can use the equation..

d = d1 + v1t + ½at²

you have to assume d1=0 /

VARUN RAJ

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Joined: 16 Mar 2008

Posts: 1825

29 Oct 2009 06:43:42 IST

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area under the graph is equal to the displacement since the slope of the line is 4............and c=-9 at displacement 1.2m y=mx +c so apply it and get h of the trinagle and the base is 1.2ms=area under vt graph =h*b/2 solve it similarly for t=3.6 s

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