Elementary Astrophysics: what is the change in the rotational angular velocity of Phobos?

Phobos is a small moon of Mars. For the purpose of the following problem, assume that Phobos has a mass of 5.8×10^15 kg and that it has a shape of a uniform sphere of radius 7.5×10^3 m. Suppose that a meteroid strikes Phobos 5.0×10^3 m off center and remains stuck. If the momentum of the meteroid was 3×10^13 kgm/s before impact and the mass of the meteroid is negligible compared with the mass of Phobos, what is the change in the rotational angular velocity of Phobos?