Solve the all parts of following question given below:
Question: Ocean waves are traveling to the east at 3.9 m/s with a distance of 21 m between crests.
Part I: With what frequency do the waves hit the front of a boat when the boat is at anchor?
Hz
Part II: With what frequency do the waves hit the front of a boat when the boat is moving westward at 1.5 m/s?
Hz
If possible just a brief explanation how you got the answer?