Answer:

Explanation:
For this problem, we need to apply the formulas of constant accelerated motion.
To obtain the boat displacement we need to calculate the displacement because of the river flow and the displacement done because of the boat motor.
for the river:

for the boat:

So the final displacement is given by:

Add all the sec. and all the meter's and then add the meter's and sec. together
<span>The correct answer should be B. a scientific law. A hypothesis is a belief by the scientist that may or may not be proven so it exists before evidence and observation, while a theory comes later. However, a law is observation itself and is always evidence of itself. There is no belief or lack of knowledge as to what will happen when it comes to laws. The law of action and reaction has plenty evidence and can easily be observed.</span>

λ - wavelength, c - the speed of light, f - frequency
![f=200 \ kHz= 200 000 \ Hz \\ \\ \lambda=\frac{300 000 \ [\frac{km}{s}]}{200 000 \ [Hz]}=\frac{3}{2}=1.5 \ [km]](https://tex.z-dn.net/?f=f%3D200%20%5C%20kHz%3D%20200%20000%20%5C%20Hz%20%5C%5C%20%5C%5C%0A%5Clambda%3D%5Cfrac%7B300%20000%20%5C%20%5B%5Cfrac%7Bkm%7D%7Bs%7D%5D%7D%7B200%20000%20%5C%20%5BHz%5D%7D%3D%5Cfrac%7B3%7D%7B2%7D%3D1.5%20%5C%20%5Bkm%5D)
The wavelength of these waves is 1.5 km.