What is the speed of the waves on the lake?

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    Lake Speed Waves
AI Thread Summary
The discussion focuses on calculating the speed of waves on a lake based on wave frequency observed from a stationary and moving boat. Initially, three waves hit the boat every 12 seconds, indicating a frequency of 0.25 Hz. When the boat moves at 1.50 m/s, only two waves hit every 12 seconds, resulting in a frequency of 0.17 Hz. The calculations reveal a mix-up in the variables for wave speed and the boat's speed, leading to confusion in the final equation. The correct interpretation of the variables is crucial for determining the accurate speed of the waves.
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Homework Statement


While anchored in the middle of a lake, you count exactly three waves hitting your boat every 12.0 s. You raise anchor and start motoring slowly in the same direction the waves are going. When traveling at 1.50 m/s, you notice that exactly two waves are hitting the boat from behind every 12.0 s.

What is the speed of the waves on the lake?

Homework Equations


f+-=(1+-v0/v)f0


The Attempt at a Solution



I have messed up this kind of problem before, so there are many places for me to make mistakes.

3 waves 12 seconds
V= 1.5m/s
2 waves 12 seconds

T1 = 4s
T2 = 6s

f1=.25
f2=.17

.17=(1-v0/1.5).25

.68=1-v0
-.32=-v0/1.5
.48=v0

I know I made a mistake somewhere...
 
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You got the overall idea for the equations but you made a slight mistake...1.5 m/s is the value of Vo (the object's velocity) and v is the velocity of the wave. You mixed the two up.
 


Thank you, that was the mistake.
 
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