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## Homework Statement

The figure shows water waves traveling between two points P and Q, 20.0 cm apart. A dust particle on the water surface makes 5 complete oscillations in 2.0 s.

What is :

i. The amplitude;

ii. The wavelength;

iii. The frequency;

iv. The speed of the waves ?

## Homework Equations

[tex]v=\lambda f[/tex]

## The Attempt at a Solution

i. amplitude = 4 cm

ii. I don't understand the question. The question states that "A dust particle on the water surface makes

**5 complete oscillations**" and I think there should be 5 waves, but in the picture there are only 2.5 waves.

The answer on the book is 8 cm. I guess it's from [tex]\lambda=\frac{20}{2.5}[/tex]

But the answer for frequency is 2.5 Hz. I guess it's from [tex]f=\frac{5\;\text{waves}}{2\;s}[/tex]

So I confused whether there are 2.5 waves or 5 waves.

Thanks