The answer to that would be that
they require so its mandatory for mechanical waves to travel through a medium
Answer:
1) The greatest height attained by the ball equals 20.387 meters.
2) The time it takes for the ball to reach 15 meters approximately equals 1 second.
Explanation:
The greatest height will be attained when the ball stop's in the air and starts falling back to the earth.
thus using third equation of kinematics we obtain the height attained as

where
'v' is the final speed of the ball
'u' is the initial speed of the ball
'a' is the acceleration that the ball is under which in this case equals 9.81 
's' is the distance it covers
Thus for maximum height applying the values in the equation we get

Using the same equation we can find the speed of the ball when it reaches 15 meters of height as

the time it takes to reduce the velocity to this value can be found by first equation of kinematics as

Answer:
h = 1.02 m
Explanation:
This is a fluid mechanics exercise, where the pressure is given by
P =
+ ρ g h
The gauge pressure is
P -
= ρ g h
In this case the upper part of the tube we have the atmospheric pressure. and the diver can exert a pressure 10 KPa below the outside pressure, this must be the gauge pressure
= P - 
= ρ g h
h =
/ ρ g
calculate
h = 10 103 / (1000 9.8)
h = 1.02 m
This is the depth at which man can breathe
A Forensic Anthropologist studies skeletal remains and gather information used to determine the individual's age at death, sex and physical condition.
So far, all we have is a very short true statement. If it's a multiple choice question, then where are they ?