Question

Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 1014 times as great as that of ordinary solid matter. Suppose we represent the star as a uniform, solid, rigid sphere, both before and after the collapse. The star's initial radius was 8.0×10⁵ km (comparable to our sun); its final radius is 17 km .

Part A

If the original star rotated once in 34 days, find the angular speed of the neutron star.

Express your answer using two significant figures

Answer 1

Change the given time into seconds. T = 35 days 2s24hr (3600 35 3024000s The initial angular speed of original star is. 27T 2π 3024000 s -0.00207 x10-3 rad/ s Let the initial moment of inertia of the star is, Let the final moment of inertia of the star is,

Use the law of conservation of momentum to find the angular speed of the neutron star, I,a C21 2 I. (mi)a m'2 i@ (8-10 km (0.00207 10'as) (17km) 4584.08rad/ s