Star A star of mass 1.17×1031 kg and diameter 7.50E+9 m rotates with a period of 23.0 days. Suddenly the st?

Star
A star of mass 1.17×1031 kg and diameter 7.50E+9 m rotates with a period of 23.0 days. Suddenly the star changes size, and rotates with a new period of 17.0 days. Assuming a uniform density both before and after the size change, what is the new diameter of the star?

DATA:
Icm=(2/5 )*mr^2

Volume= (4/3)pi^2

Area=4?r^2

(in m(

Chosen Answer:
We use conservation of angular momentum I*? where ? = 2?/T

I (initial) = 2/5*M*ri^2 and I (final) = 2/5*M*rf^2

So 2/5*M*ri^2* 2?/(23*24*3600) = 2/5*M*rf^2*2?/(17*24*3600)

Simplifying we

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