m = 2kg, u = 4 m/s, F = -6 N, t = 3 s
From Newton's second law of motion,
F = m * a
= m * (v-u)/t
Therefore,
-6 = 2 * (v-4)/3
(v-4) = -9
v = -5 m/s
(Note : The negative velocity indicates that the ball has a net velocity in the direction opposite of it's initial motion, i.e it is stopping)
