First we need to find the speed of the dolphin sound wave in the water. We can use the following relationship between frequency and wavelength of a wave:

where
v is the wave speed

its wavelength
f its frequency
Using

and

, we get

We know that the dolphin sound wave takes t=0.42 s to travel to the tuna and back to the dolphin. If we call L the distance between the tuna and the dolphin, the sound wave covers a distance of S=2 L in a time t=0.42 s, so we can write the basic relationship between space, time and velocity for a uniform motion as:

and since we know both v and t, we can find the distance L between the dolphin and the tuna:
A spring that obeys Hooke's law has a spring force constant of 272 N/m. This spring is then stretched by 28.6 cm
You get the net force acting on it ... the sum of the strengths and directions
of all the individual forces there may be.
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus