Answer:
a)
, b) 
Explanation:
a) The maximum height is obtained with the help of the First and Second Derivative Tests:
First Derivative



Second Derivative
(absolute maximum)
The maximum height reached by the ball is:


b) The time required by the ball to hit the ground is:




Just one root offers a solution that is physically reasonable:

The velocity of the ball when it hits the ground is:


D. Collect more evidence and try to convince the other scientist
Answer:
12.64968 Hz
Explanation:
v = Velocity of sound in seawater = 1522 m/s
u = Velocity of dolphin = 7.2 m/s
f' = Actual frequency = 2674 Hz
From Doppler effect we get the relation

The frequency that will be received is 2661.35032 Hz
The difference in the frequency will be
