The mass of a star is 1.45.1031 kg and its angular velocity is 1.60E-7 rad/s. Fi
ID: 1394563 • Letter: T
Question
The mass of a star is 1.45.1031 kg and its angular velocity is 1.60E-7 rad/s. Find its new angular velocity if the diameter suddenly shrinks to 0.49 times its present size . Assume a uniform mass distribution before and after. 1cm for a solid sphere of uniform density is 2/5 mr2.The mass of a star is 1.45.1031 kg and its angular velocity is 1.60E-7 rad/s. Find its new angular velocity if the diameter suddenly shrinks to 0.49 times its present size . Assume a uniform mass distribution before and after. 1cm for a solid sphere of uniform density is 2/5 mr2.
Explanation / Answer
Let, R1 = R, w1 = 1.6*10^-7 rad/s
and R2 = 0.49*R, w2 = ?
Apply conservation of angular momentum
I1*w1 = I2*w1
(2/5)*M*R1^2*w1 = (2/5)*M*R2^2*w2
w2 = w1*(R1/R2)^2
= w1*(R/(0.49*R))^2
= 4.16*w1
= 4.16*1.6*10^-7 rad/s
= 6.66*10^-7 rad/s <<<<<<---------Answer
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