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Jason17
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Homework Statement
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
Homework 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
The Attempt at a Solution
So I am 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