14 right??? i hope this helps
30 kg m/s
momentum = mass x velocity = 10 x 3 m/s =30 kg m/s
The given reaction is,

In this reaction, the positive and negative ions of both the reactants rearrange resulting in the formation of new compounds. Such a reaction is referred to as the double replacement or the double displacement reaction. These type of reactions usually take place in aqueous medium and one of the products is a precipitate.
Double displacement reactions are of three types, precipitation reaction, neutralization reaction and reaction involving the formation of a gas. The given reaction is a precipitation reaction as one of the products is a solid.