Question

One particular neutron star has a mass equal to 3.00 times the mass of the sun. You may consider this neutron star to be a sphere with a uniform density of 3.30×10¹⁷ kg/m3 !! ......compare that to the density of lead for example, at 1×10⁴ kg/m3 . (A neutron star is created when a massive star runs out of hydrogen fuel and collapses at the end of its life. The neutron star is a very dense and spins rapidly). If needed, the mass of the sun is 1.99×10³⁰ kg

Part A

What's the rotational inertia of the neutron star?

Express your answer with the appropriate units.

INS =

SubmitRequest Answer

Part B

The neutron star's spin rate slowly decreases as a result of torque associated with magnetic forces. If the spin-down rate is   4.50  ×10?5 rad/s2, what's the magnitude of the magnetic torque?

Express your answer with the appropriate units.

? =

Answer 1

A)
Mass of the star, M = 3*Ms

= 3*1.99*10^30

= 5.97*10^30 kg

let R is the radius of the star.

we know,

density = mass/volume

volume = mass/density

(4/3)*pi*R^3 = 5.97*10^30/(3.30*10^17)

R = 16285 m

the rotational inertia of the neutron star,

I = (2/5)*M*R^2

= (2/5)*5.97*10^30*16285^2

= 6.33*10^38 kg.m^2 <<<<<<<<<<------------------Answer

B) we know,

Torque = I*alfa

= 6.33*10^38*4.5*10^-5

= 2.85*10^34 N.m <<<<<<<<<<------------------Answer