Respuesta :
Based on law of conservation of angular momentum, the rotational speed of the star is equal to 6,000 rev/s.
Given the following data:
- Radius of Sun = 7 × 10⁵ km.
- Mass of star = 2 Mass of Sun (M = 2M).
- Radius of star = 10 km.
- Time = 10 days.
How to calculate the rotational speed.
First of all, we would determine the initial angular speed of the neutron star as follows:
[tex]\omega_i = \frac{1 \;Rev}{10 \;days} \\\\\omega_i = \frac{1 \;Rev}{10 \times 24 \times 60 \times 60}\\\\\omega_i = 1.157 \times 10^{-6}\;rev/s[/tex]
Mathematically, the moment of inertia of a uniform solid sphere is given by this formula:
[tex]I=\frac{2}{5} mr^2[/tex]
Where:
- I is the moment of inertia.
- m is the mass.
- r is the radius.
In order to determine the rotational speed of this neutron star, we would apply the law of conservation of angular momentum:
[tex]L_1 = L_2\\\\I_1\omega_1 = I_2\omega_2\\\\\frac{2}{5} m_1r_1^2 \omega_1 = \frac{2}{5} m_2r_2^2\omega_2\\\\m_1r_1^2 \omega_1 = m_2r_2^2\omega_2\\\\\omega_2 =\frac{r_1^2 \omega_1}{r_2^2}[/tex]
Substituting the given parameters into the formula, we have;
[tex]\omega_2 = \frac{ (7 \times 10^5 )^2 \times 1.157 \times 10^{-6}}{ (10 )^2}\\\\\\\omega_2 = \frac{ (7 \times 10^5 )^2 \times 1.157 \times 10^{-6}}{ 10 0}\\\\\omega_2 =\frac{566,930}{100}[/tex]
Final angular speed = 5,669 ≈ 6,000 rev/s.
Read more on inertia here: https://brainly.com/question/3406242