Question

When a stone is dropped into a pond, ripples form and move in concentric circles outward from the location of the stone impact. As the ripples move outward, they lose waves lose amplitude. If we neglect friction, why would the wave amplitude decrease the further they move outward?

Answer 1

Step-by-step explanation:

When a stone is dropped into a pond, ripples form and move in concentric circles outward. This can be treated as a point source emitting waves. And for point source emitting waves

Intensity of the wave I = Source power Ps/Area

⇒
`I= (Ps)/(\pi r^2)`

⇒I∝1/r^2

Therefore, on increasing the distance r, the intensity of the wave decreases, this also means that the amplitude also decreases.