# Destructive Interference with a Pebble

1. Apr 27, 2008

### luvinlife

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

A pebble is dropped in a lake; and it produces ripples with a frequency of .25 Hz. When should a second pebble be dropped at the same place to produce destructive interference

2. Relevant equations
I'm not even sure if these apply, but they are the only formulas I know.

v=f$$\lambda$$ or v=$$\lambda$$/t

3. The attempt at a solution

I have no idea how to solve this problem

2. Apr 27, 2008

### CrazyIvan

What will the second pebble's wave look like? How do these two waves "add up"?

In what way do you want them to "add up" in order to get destructive interference

3. Apr 27, 2008

### luvinlife

I get it!
wow.. definitely over thought that one.
Thank you for the thought provoking questions.