Question

An earthquake 45 km from a city produces P and S waves that travel outward at 5000 m/s and 3000 m/s, respectively. Once city residents feel the shaking of the P wave, how much time do they have before the S wave arrives in seconds?

Answer 1

The S wave arrives 6 sec after the P wave.

Step-by-step explanation:

Given that,

Distance of P = 45 km

Speed of p = 5000 m/s

Speed of S = 3000 m/s

We need to calculate the time by the P wave

Using formula of time

`t = (D)/(v)`

Where, D = distance

v = speed

t = time

Put the value in to the formula

`t_(p) =(45*1000)/(5000)`

`t_(p) = 9\ sec`

Now, time for s wave

`t_(s)=(45000)/(3000)`

`t =15\ sec`

The required time is

`\Delta t=t_(s)-t_(p)`

`\Delta t=15-9`

`\Delta t =6\ sec`

Hence, The S wave arrives 6 sec after the P wave.