Answer:
Speed,

Step-by-step explanation:
Given that,
Radius of the neutron stare, R = 20 km = 20,000 m
Time taken by the Neutron star to rotate, t = 1 s
We need to find the speed of a particle on the star's equator. The total distance covered divided by total time taken is called speed of an object. Here,


v = 125663.70 m/s
or

So, the speed of a particle on the star's equator is
. Hence, this is the required solution.