A constant force applied to object A causes it to accelerate at 6 {rm m/s^2}.The same force applied to object B causes an acceleration of 3 {rm m/s^2}. Applied to object C, it causes an acceleration of 9 {rm m/s^2}.
3 Answers

The 2nd law of Newton :
F = m * a
–> F = mA * 6
—> F = mB * 3
mA * 6 = mB * 3
—> mA/mB = 3/6 = 1/2

Ratio of mass of object A to that of B = acceleration of B /acceleration of A = 3/6 = 1/2

If acceleration of B compared to A is halved, it has twice the mass of A.
If C is accelerated at 3 x the rate of B, it has 1/3rd. the mass of B. It has also therefore, 2/3rds. the mass of A.
Source(s): Just logic.