The asteroid's velocity component tangent to the surface of the planet at the equator is:
│v│∙ sin 40o
This times the mass of the asteroid gives the impulse (F∙t) the asteroid gives to
the planet, tangent at the point of impact and in the direction of the planet rotation:
m∙│v│∙ sin 40o
This time the radius of the planet gives the increment in angular momentum of
the planet:
R∙│v│∙ sin 40o