You are standing on the beach counting waves. you use the pier to estimate that there is 5 m between wave crests and you measure that a wave takes 2 seconds to pass your location. what is the speed of the wave?

2.5 m/s

Explanation:

In this problem, we know:

is the wavelength of the wave (distance between two successive crests)

is the period of the wave (the time it takes a wave to pass the location)

From the period, we can find the frequency of the wave:

And now we can find the speed of the wave by using the following equation:

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.