Physics Two Dimensional Motion Question 275

Question: Certain neutron stars are believed to be rotating at about $ 1,rev/\sec $ . If such a star has a radius of 20 km, the acceleration of an object on the equator of the star will be

[NCERT 1982]

Options:

A) $ 20\times 10^{8}m/{{\sec }^{2}} $ B) $ 8\times 10^{5}m/{{\sec }^{2}} $ C) $ 120\times 10^{5}m/{{\sec }^{2}} $ D) $ 4\times 10^{8}m/{{\sec }^{2}} $

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Answer:

Correct Answer: B

Solution:

$ a={{\omega }^{2}}r=4{{\pi }^{2}}n^{2}r=4{{\pi }^{2}}\times 1^{2}\times 20\times 10^{3} $ \ a=$ 8\times 10^{5}\ m/{{\sec }^{2}} $