4. Identify Problems A student is describing a longitudinal wave in his notebook. He
writes down "The distance between crests is 3 cm." What is wrong with what the
student recorded?

 "The distance between crests is 3 cm." 

Explanation:

If he writes down "The distance between crests is 3 cm." 

That means he is describing the wavelength of a wave and not longitudinal wave. He ought to write something about " direction "

Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or parallel to, the direction of propagation of the wave. While

Wavelength is the distance between the two successfully Crest or trough

there are no contact forces mentioned on the list of choices that you've provided.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min