Question

Please xplain about qualitative definition of momentum ??

Answer 1

qualitatively - a measure of an object's mass to resist changes in its velocity or acceleration.

Not quite so. An object's momentum is not a intrinsic characteristic of the object, it will be whatever it is; that's not the same as the MASS, which *CAN* be defined as a factor which gives a measure of how much the object resists changes in momentum. You can rewrite Newton's second law as such:
F = dp/dt
with p=mv. Remember that not all problems hold that the mass m is constant; for example, you wouldn't be able to give dm/dt=0 for a rocket, which sheds its "fuel" as it is consumed -- hence, although F=dp/dt holds, the rocket's total mass varies with time (dm/dt < 0)...