# How to calculate striking speed of a meteor?

A neutron star has radius $10$km and mass $2.5\times 10^{29}$kg. A meteorite is drawn into its gravitational field. Calculate the speed with which it will strike the surface of the star. Neglect the initial speed of the meteorite.

In the solution provided, we use the formula for escape speed, which is

$$v = \sqrt{\frac{2GM}{R}}$$

But the derivation of the formula for escape speed involves a mass has zero kinetic energy and zero gravitational potential energy.

So, my question is: Why can we use escape speed to calculate striking of a meteor in this case?

$$1/2mv^2 = MG/R$$