Certain neutron stars (extremely dense stars) are believed to be rotating at about 14 revs/s.
if such a star has a radius of 25 km, what must be its minimum mass so that material on its surface remains in place during the rapid rotation?

Explanation:

G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²

M = Mass of the star

m = Mass of object at a distance r

r = Radius = 25 km

N = 14 rev/s

The gravitational force of will balance the centripetal acceleration

Velocity is given by

The mass of the neutron star is

statement #3 on andre"s list is false.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me