A) 8.11 m/s
For a satellite orbiting around an asteroid, the centripetal force is provided by the gravitational attraction between the satellite and the asteroid:

where
m is the satellite's mass
v is the speed
R is the radius of the asteroide
h is the altitude of the satellite
G is the gravitational constant
M is the mass of the asteroid
Solving the equation for v, we find

where:




Substituting into the formula,

B) 11.47 m/s
The escape speed of an object from the surface of a planet/asteroid is given by

where:




Substituting into the formula, we find:

Answer:
The magnitud of the velocity is

and the direccion:
degrees from the horizontal.
Explanation:
Fist we define our variables:

The letters i and j represent the direction of the movement, i in this case is the horizontal direction, and j is perpendicular to i.
velocities with sub-index 1 are the speeds before the crash, and with sub-index 2 are the velocities after the crash.
Using conservation of momentum:

Clearing for the velocity of the stone after the crash:

Substituting known values:

The magnitud of the velocity is :

and the direction:

this is -28.3 degrees from the +i direction or the horizontal direcction.
Note: i and j can also be seen as x and y axis.