The momentum of an object is given by:
[tex]p=mv[/tex]
where
p is the momentum
m is the mass
v is the velocity of the object
The ball in our problem has a mass of m=1.0 kg and a momentum of [tex]p=12 kg m/s[/tex], therefore we can use the previous formula to find its velocity:
[tex]v= \frac{p}{m}= \frac{12 kg m/s}{1.0 kg}=12 m/s [/tex]