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 are the
fastest. The speed of P waves is approximately 7 km/s, and that of S waves is about 4 km/s. People do not generally feel the P waves, but animals seem to be sensitive to them. If a person reports that her dog started barking 20 seconds "before the earthquake," then approximately how far was the origin of the earthquake? A) 100 km
B) 200 km
C) 300 km
D) 400 km
E) 500 km
B
You might also like to view...
Which statement must be true for a rocket to travel from Earth to another planet?
A) It must attain escape velocity from Earth. B) It must carry a lot of extra fuel. C) It must have large engines. D) It must be launched from space, rather than from the ground.
What is the one piece of evidence that suggests that the dinosaurs were made extinct by the impact of an asteroid 65 million years ago?
A) the crater from this impact can still be seen in the deserts of Arizona B) a layer of sediment laid down at that time contains grains of shocked quartz, solidified rock droplets, and soot from global wildfires C) a layer of sediment laid down at that time is littered with dinosaur fossils D) dinosaur fossils are found in rock layers older than 65 million years but not younger than 65 million years
Astigmatism is due to too flat a cornea
Indicate whether the statement is true or false
Force on a Moving Charge: A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component
A. towards the west. B. towards the east. C. towards the south. D. towards the north. E. downward.