well a simple way to investigate this is to use the formula
Force = Mass x Acceleration
so if force is constant say 10 units
10 = mass x acceleration
if the mass is 5 units the acceleration is 2 units
if the mass is 1 unit the acceleration is 10 units
if the mass is 1/2 units the acceleration is 20 units
so hopefully you can see a pattern occurring that you can generalise for your answer
