An earthquake generates three kinds of waves: surface waves (L waves), which are the slowest and weakest; shear (S) waves, which are transverse waves and carry most of the energy; and pressure (P) waves, which are longitudinal waves and travel the fastest. The speed of P waves is approximately 7.0 km/s, and that of S waves is about 4.0 km/s. Animals seem to feel the P waves. If a dog senses the arrival of P waves and starts barking 39.5 s before an earthquake is felt by humans, approximately how far is the dog from the earthquake’s epicenter? pleaaseeee !!! ('drwls' 369 miles is wrong answer :( ! can you calculate with meter pleasee )

http://www.jiskha.com/display.cgi?id=1319462909

bobpursley 369 km is true!! thnx very much ! But if starts barking is 23.3 s ?? what is answer ?? can you calculate please !

i found it ! thankssss

A sinusoidal wave on a string is described by the equation y = (0.169 m) sin (0.713 x - 41.9 t), where x and y are in meters and t is in seconds. If the linear mass density of the string is 10.1 g/m ...

a) ... the phase of the wave at x = 2.27 cm and t = 0.175 s. ?
b)... the speed of the wave ?
c)... the wavelength.
d) ... the power transmitted by the wave. ?

To find the distance from the earthquake's epicenter, we can use the fact that the difference in arrival time between P waves and S waves is related to the distance from the epicenter.

Let's assume that the dog sensed the arrival of P waves 39.5 seconds before humans felt the earthquake. The time difference between the arrival of P waves and S waves is around 39.5 seconds as well.

The speed of P waves is approximately 7.0 km/s, and the speed of S waves is about 4.0 km/s.

First, we need to calculate the distance traveled by both types of waves during the time difference. We can use the formula: distance = speed × time.

For P waves:
Distance of P waves = 7.0 km/s × 39.5 s = 276.5 km

For S waves:
Distance of S waves = 4.0 km/s × 39.5 s = 158 km

Next, we can find the difference between the distances traveled by the P and S waves:
Difference in distance = Distance of P waves - Distance of S waves
= 276.5 km - 158 km
= 118.5 km

Finally, we need to convert the distance to meters. Since 1 km is equal to 1000 meters, the distance is:
Distance = 118.5 km × 1000 m/km = 118,500 meters

Therefore, the dog is approximately 118,500 meters away from the epicenter of the earthquake.