A group of swimmers is resting in the sun on an off-shore raft. They estimate that 2.5 m separates a trough and an adjacent crest of surface waves on the lake. They count 15 crests that pass by the raft in 15 s. How fast are the waves moving?
____m/s
(I got these answers and none of them were correct)
.17
6.07
6.05
5.56
4.86
4.9
5.6
4.85
frequency*wavelength=speed
15/15 * 2*2.5=speed
I am wondering how you got any of those answers?
I have no idea. I'm pretty sure I used 2.6 instead of 2.5 on accident! OOPS
To find the speed of the waves, we can use the formula:
Speed = Wavelength / Period
Given that the distance between a trough and an adjacent crest is 2.5 m, this is equal to half the wavelength:
Wavelength = 2 * 2.5 m = 5 m
The period is the time it takes for one complete wave (crest to crest) to pass by. In this case, the period is 15 s for 15 crests.
Period = Time / Number of crests
Period = 15 s / 15 crests = 1 s/crest
Now, we can substitute the values into the formula:
Speed = Wavelength / Period
Speed = 5 m / (1 s/crest)
Simplifying the expression:
Speed = 5 m/s
Therefore, the speed of the waves is 5 m/s.
To calculate the speed of the waves, we can use the formula:
Wave speed = Distance between crests / Time for one crest to pass by
In this case, the distance between crests is given as 2.5 meters, and the time it takes for one crest to pass by is 15 seconds. So we can substitute these values into the formula to find the wave speed:
Wave speed = 2.5 m / 15 s = 0.1667 m/s
Therefore, the correct answer would be approximately 0.17 m/s.
It seems like you tried calculating the wave speed correctly, but the values you provided might have been rounded differently or had rounding errors during calculations. Make sure to use the exact values and round appropriately to get the accurate answer.