Suppose a ball is dropped from shoulder height, falls, makes a perfectly elastic collision with the floor, and rebounds to shoulder height. compare the magnitudes of the impulses delivered to the ball by gravity and by the floor during this entire motion.

Same magnitude

Explanation:

When ball is dropped from shoulder height h then velocity at the bottom is given by

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

Thus impulse imparted by gravity and Floor will have same magnitude of impulse but direction will be opposite to each other.