As per Newton's II law we know that
[tex]F = ma[/tex]
here F = force applied
m = mass of object = 2 kg
a = acceleration = 2 m/s^2
now as per above formula we will have
[tex]F = 2 \times 2[/tex]
[tex]F = 4 N[/tex]
so here applied force on the ball will be 4 N