# Speed of waves

1. Nov 7, 2007

### BarCode

1. The problem statement, all variables and given/known data

The wavelength of a water wave is 8.0m and its speed is 2.0m/s. How many waves will pass a pixed point in the water in 1.0min?

2. Relevant equations

V =f(lambda)

3. The attempt at a solution

As far as I got was that 1.0 min = 60 seconds. From there, I am totally lost.

2. Nov 7, 2007

### Kurdt

Staff Emeritus
Frequency measures the number of waves that pass a fixed point per unit time. Does that help any?

3. Nov 7, 2007

### BarCode

F = 1/T, which is all I know.

4. Nov 7, 2007

### Kurdt

Staff Emeritus
Well if you can work out the frequency which tells you how many waves pass a point per second then you can use that to work out how many waves pass in a certain number of seconds.

5. Nov 7, 2007

### BarCode

I get confused as to how to know which number to use for the denominator.

6. Nov 7, 2007

### Kurdt

Staff Emeritus
What is the frequency first of all?

7. Nov 7, 2007

### BarCode

F = 1/T
T = P = 8.0m / 2.0s = 4s

F = 1/4

8. Nov 7, 2007

### Kurdt

Staff Emeritus
so if one quarter of a wave passes a fixed point every second, how many pass that fixed point in 60 seconds?

9. Nov 7, 2007

### BarCode

60/4
= 15 waves in 60 seconds.

10. Nov 7, 2007

### Kurdt

Staff Emeritus
That looks fine to me.