a body of mass 0.5kg undergoes a change of velocity of 4cm/s in 4 second .what is the force acting on it?????

as change =acceleration=4cm/sec = 4/100 m/s

and force = mass X acceleration

mass =0.5kg and acceleration =change / time =4/100/4=1/100

now force = 5/10 X 1/100 = 1/200 =0.005