Answer:
The minimum mass so that material on its surface remains in place during the rapid rotation is [tex]5.03\times 10^{22}\ kg[/tex].
Explanation:
Given that,
Certain neutron stars are believed to be rotating at about 0.70 rev/s.
Radius of the star, r = 119 km
When the star rotates the gravitational force is balanced by the centripetal force as :
[tex]G\dfrac{Mm}{r^2}=m\omega^2 r\\\\M=\dfrac{\omega^2r^3}{G}\\\\M=\dfrac{(0.7)^2\times (19000)^3}{6.67\times 10^{-11}}\\\\M=5.03\times 10^{22}\ kg[/tex]
So, the minimum mass so that material on its surface remains in place during the rapid rotation is [tex]5.03\times 10^{22}\ kg[/tex].
