JEE mechanics doubt!! plz help

Q. If angular velocity of a disc depends on angle rotated θ\theta as ω\omega =θ2\theta^{2} +2θ2\theta, then its angular acceleration α\alpha at θ\theta=1 rad is

(1) 8 rad/sec2sec^{2}
(2) 10 rad/sec2sec^{2}
(3) 12 rad/sec2sec^{2}
(4) None of these
The answer is (3) but i am not getting a solution so someone please help by providing one. Thanks!

Note by Akhilesh Chobey
5 years, 5 months ago

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1 vote

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First differentiate omega with respect to t to get the expression of alpha then put the value of omega at theta 1 and theta

Vipra Goyal - 5 years, 1 month ago

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i think angular acc is dw/dt to find that : first find dw/dtheta and then as we know w = dtheta/dt

so now take out inverse of w which is dt/dtheta and now divide dw/dtheta and dt/dtheta

vaibhav Chaturvedi - 4 years, 3 months ago

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since a(alpha) = dw/dt = (dw/ds )(ds/dt)=w(dw/ds).Hence ans will be 3*4=12

PIYUSH BHARTI - 4 years, 1 month ago

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