Question

Do large damping force on a body means large change in amplitude why?

Answer 1

Damping is energy lost to heat, as in a car's shock absorber, and since energy of a system is proportional to amplitude, it will reduce it.

Explanation:

An totally undamped system will oscillate forever. For example a tuning fork. But the 2nd Law of Thermodynamics says that systems tend to the lowest energy state possible and thus the amplitude will eventually decrease to zero if not driven with more energy of some kind.