Answer: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.
Answer:
An object may become extinct due to the lack of quantity of the object and the object no longer exists so it is now extinct.
Answer:
B.) by interfering with sound waves
Explanation:
As we know that the interference of sound waves is of two types
1). constructive interference
2). destructive interference
now we know that constructive interference means the resultant intensity will be more than the intensity of interfering waves as here two waves are in same phase.
In destructive interference the resultant of two waves is given by the minimum resultant of the intensity as here the phase of two waves are opposite to each other.
So we will say that

here in case of noise cancelling headphones we know that the phase of noise is always made in opposite phase with the sound which is used to cancelled the noise.
This will reduce the noise and we will get a clear sound