(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A recording station observed that there was an interval of 68s between the reception of P (push or primary) waves and S (shake or secondary waves) from an underground nuclear test explosion.

The speed of P and S waves in the Earths crust are 7800 ms^-1 and 4200 ms^-1, respectively.

Calculate the distance of the test site from the explosion

2. Relevant equations

Speed = Frequency x wavelength (v=fλ)

Speed of electromagnetic radiation = 3 x 10^8 ms^-1

Speed of sound in air 340 ms^-1

Speed of sound in water and sea water = 1500 ms^-1

3. The attempt at a solution

So im using this formula:

Speed = Frequency x wavelength (v=fλ)

I have the speed, 7800 & 4200 and its frequency i believe? is 68 seconds

Im trying to find the distance (is this the wavelength?)

Wavelength= Speed/Frequency

The answer is 620 km. Which i cannot get to :\

Help appreciated, ty in advance

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# Homework Help: Calculate distance from expolision - Waves

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