The impulse given to a ball with mass of 4 kg is 16 n s. if the ball starts from rest, what is its final velocity?

The formula for impulse is F*(t₂-t₁)=m*(v₂-v₁), where F is the force, t is time, m is mass and v is velocity. 

In our case m*(v₂-v₁)=16 N s, m=4 kg, v₁=0 and t₁=0.

m*(v₂-0)=16 N s, we solve for v₂:

4*v₂= 16

v₂=16/4

v₂=4 m/s

So the final velocity of the ball is v₂=4 m/s.