A group of swimmers is resting in the sun on an off shore raft. They estimate that 1.1m separates a trough and an adjacent crest of surface waves on the lake. In addition, they count 23 crests that pass by the raft in 15.7seconds.
What is the frequency of these surface waves?
How fast are the waves moving?
To calculate the frequency of the surface waves, you need to know the time it takes for one wave to pass by the raft. In this case, the given information is the number of crests that pass by the raft and the time it takes for them to pass.
The formula to calculate the frequency of the waves is:
Frequency = Number of crests / Time
From the given information, we know that 23 crests pass by the raft in 15.7 seconds. Plugging these values into the formula, we have:
Frequency = 23 crests / 15.7 seconds
Now we can calculate the frequency.
To determine the speed at which the waves are moving, we need to know the wavelength of the waves and the time it takes for one wave to pass by the raft. The wavelength is the distance between two consecutive crests or troughs.
In this case, the given information is the distance between a trough and an adjacent crest, which is 1.1m, and the time it takes for 23 crests to pass by the raft, which is 15.7 seconds.
To calculate the wavelength, we divide the total distance traveled by the number of crests:
Wavelength = Distance / Number of crests
Wavelength = 1.1m / 23
Once we have the wavelength, we can determine the speed of the waves using the formula:
Speed = Wavelength / Time
Speed = (1.1m / 23) / 15.7 seconds
Now you can perform the calculations to find the frequency of the waves and the speed at which they are moving.