Amplitude of waves at a further distance

[JessicaHelena]

Homework Statement

While sitting in a large pool that has a wave generator situated in the center, you text your friend, who is sitting much closer to the wave generator. If the amplitude of the generated wave is A at your friend's location from the generator (d=5.0m), what is the amplitude of the wave at your location farther away (d=50m)? Assume the pool is very large such that the reflection and superposition of waves is not a factor.

A) 10 A
b) 3.16 A
C) 0.1 A
D) 0.316 A

Homework Equations

The problem is I actually have no idea how to approach this question.

The Attempt at a Solution

I had thought that the amplitude would stay the same, but since none of the answers has just A, it seems that energy is being lost. Then at a distance further away, the amplitude should be less than A, but I am not sure how to mathematically solve this and so can't determine between C) and D).

 

[tnich]

Homework Statement

While sitting in a large pool that has a wave generator situated in the center, you text your friend, who is sitting much closer to the wave generator. If the amplitude of the generated wave is A at your friend's location from the generator (d=5.0m), what is the amplitude of the wave at your location farther away (d=50m)? Assume the pool is very large such that the reflection and superposition of waves is not a factor.

A) 10 A
b) 3.16 A
C) 0.1 A
D) 0.316 A

Homework Equations

The problem is I actually have no idea how to approach this question.

The Attempt at a Solution

I had thought that the amplitude would stay the same, but since none of the answers has just A, it seems that energy is being lost. Then at a distance further away, the amplitude should be less than A, but I am not sure how to mathematically solve this and so can't determine between C) and D).

At 5m, the ripple forms a circle of circumference 10π. What is the circumference at 50m? How does the energy per meter of circumference change with the radius? How does the amplitude change with the energy?