A stone is thrown into a quiet pool of water. With no fluid friction, the amplitude of the waves falls off with distance r from the impact point as A) 1/r³ B) 1/r² C) 1/r^3/2 D) 1/r^1/2 E) 1/r

Question

Quizplus · Accepted Answer

In a three-dimensional wave spreading out from a point (like ripples in a pool), the amplitude of the wave decreases as the inverse square root of the distance from the source. This is because the energy of the wave spreads out over the surface of a sphere, and the surface area of a sphere increases with the square of the radius (4πr^2). Therefore, the correct answer is $1/\sqrt{r}$, which corresponds to choice D.

A Stone Is Thrown into a Quiet Pool of Water