physics
posted by maria on .
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 !!!

Shear (S) waves arrive next, after P.
For each kilometer distance from epicenter, there is a delay of 1/4  1/7 = 0.107 seconds between those two waves.
A 39.5 second delay means the distance is 369 miles. 
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 )

distancein km= 1km/.107*39.5s=369km

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 23.3 s before an earthquake is felt by humans, approximately how far is the dog from the earthquake’s epicenter?