Physical development , Cognitive Development , psychosocial development I think!
The frequency, the speed and the wavelength of a wave are related by the following equation:

(1)
where
f is the frequency

is the wavelength
v is the wave speed
The speed of the wave does depend only on the properties of the medium, so since the wave is still traveling in air, the medium has not changed and therefore the speed remains the same. We see instead from eq.(1) that the frequency is inversely proportional to the wavelength, so if the wavelength is decreased by half, we see that the frequency will double.
D.
Sasha is informing participants about the study and making sure they wish to participate.
Answer:
The dolphin's speed is 17 mi/h
Explanation:
Use the formula for average velocity: Distance/time
then the average speed of the dolphin is 51/3 mi/h = 17 mi/h
Momentum is a vector, although we don't hammer on that. In order to completely describe a momentum, you need a magnitude AND a direction ... just like force and velocity.
So choice #2 is the magnitude of a momentum, without its direction.
<em>Choice #3</em> is the full package, with both the magnitude and the direction.
Choice #1 has units of energy, and choice #4 has units of acceleration, so neither of those can be it.