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

Answer: I feel that 3 is the answer
Explanation: Let there be 2 objects, A and B
A is at height of 5m whereas B is at height of 15m
so over here let the gravitational potential energy of A be x
and since B is 3 times higher than A B=3x
Since, earth is considered to be the point where gravitational potenial is 0
So hence forth and object 3 times up will have 3 times the gravitational potential energy of A
<span>B.Shape of continents look like puzzle pieces that can fit into one another</span>