Answer:Same magnitude
Explanation:
When ball is dropped from shoulder height h then velocity at the bottom is given by
[tex]v_1=\sqrt{2gh}[/tex]
if it makes elastic collision then it will acquire the same velocity and riser up to the same height
If m is the mass of ball then impulse imparted is given by
[tex]J=m(v_2-v_1)[/tex]
[tex]J=2m\sqrt{2gh}[/tex]
Thus impulse imparted by gravity and Floor will have same magnitude of impulse but direction will be opposite to each other.