Wave speeds A water wave passes a boat. An observer on the boat notices that 1212] water waves pass the boat in a time of '1 minute. The boat is at anchor and it is not travelling through the water. Calculate the frequency.r of the water waves in hertz: Hz. The water waves have a wavelength of 1.8 m. Calculate the wave speed of the water waves. The table below shows values for wavelength, frequency: time period. and wave speed. Fill in the missing values in the table and identify.r what the wave might be. Wavelength Time period Wave 5 int} {5} lmls} Elli-(10'? Silly-{103 28 DDU 157T} (2 marks] (3 marks] (9 marks] 3 A sound wave is generated by clapping two wooden sticks together. The students record hearing the echo \"1.2 seconds later. The students are standing 21D m from the 1.Ivall. g Use this information and the diagram to determine a value for the speed of sound in air. [4' marks} t; Explain how the investigation could be changed so that the value for the speed of sound obtained would be more accurate. [2 marks} 4 An ultrasound signal is sent out by a ship to detect how far beneath the surfaoe the sea bed is. The process is called 'echoranging'. The ultrasound signal has a frequency:r of 24 {101'} Hz and a wavelength of {1.63 m. The time between sending the signal and detecting the reected wave is [1.42 s. echo-minder g Explain why the process is called echoranging. {2 marks} b Explain why the equation used to nd the distanoe of the sea bed beneath the surface can be written as d = 1E {v x r} {2 marks} ; Calculate the distance from the surface of the water to the sea bed. {4 marks)