the speed of sound in seawater is 1470 m/s. a dolphin sends out a click that reflects off of an
object 150.0 m away. how long does it take from the initial click for the echo to return to the
dolphin?

0.204 s

Explanation:

The speed of sound is defined as the distance traveled in a especific time :  

Where:  

is the speed of sound  in seawater

is the time the sound wave travels from the dolphin and then returns after the reflection

is twice the distance between the dolphin and the object to which the sound waves are reflected

Finding :

Finally:

a

explanation:

no diagram was provided, but i'm guessing it's the one i've attached to my answer.

here, a mechanical force turns the rod.   this generates an electric current in the coil, which powers the bulb.

the answer is kevlar