According to Newton's second law of motion, the impulse applied to an object is equal to the change in momentum of the object. Mathematically, this can be expressed as:

Impulse = Final momentum - Initial momentum

Since the ball starts from rest, its initial momentum is zero. Therefore, the impulse applied to the ball is equal to its final momentum.

Substituting the given values, we have:

16 Nsec = 4 kg × Final velocity

Solving for the final velocity, we get:

Final velocity = 16 Nsec / 4 kg = 4 m/s

Therefore, the final velocity of the ball is 4 m/s.