An earthquake emits both P-waves and S-waves that travel at different speeds through the Earth. A P-wave travels at 8 000 m/s and an S-wave at 4 000 m/s. If P-waves are received at a seismic station 30.0 s before an S-wave arrives, how far is the station from the earthquake center?

240Km

Explanation:

For each wave, we calculate the time taken to travel the required distance. The time taken for wave P can be computed as

distance=Speed * time

Distance=8000t...........equation 1

For wave S which was received 30secs later the the total time of travel is

(t+30)

Hence the distance covered is

Distance=4000(t+30)............equation 2

If we equate both equations we arrive at

Hence the distance travel by any of the wave will give the required distance

Distance traveled by wave P is from equation 1

Distance=8000t

Distance=8000*30

Distance=240,000m

Distance=240Km

spectral lines lyman is one set

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.