A 0.5 m long string with a linear mass density of 0.005 kg/m is supported between two stands and plucked causing it to vibrate. What is the frequency of the second mode if the tension of the string is 200 N

Afisherman notices that his boat is moving up and down periodically, owing to waves on the surface of the water. it takes a time of 2.70 s for the boat to travel from its highest point to its lowest, a total distance of 0.700 m. the fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart. a. how fast are the waves traveling? b. what is the amplitude a of each wave?