A seismographic station receives S and P waves from an earthquake, separated in time by 16.2 s. Assume the waves have traveled over the same path at speeds of 4.50 km/s and 8.20 km/s. Find the distance from the seismograph to the focus of the quake.

1. In still air, with a speed of sound, v= 343.0m/s, a source of sound A is moving directly toward a reflecting surface B. Reflecting surface B is moving directly away from source A. The speed of A is v, =162 km / h and the speed of B is VR = 86.4 km / h. Sound source A emits waves of frequency f, =1200.0 Hz in the frame of A. а. What is the frequency heard by a detector mounted on and moving with reflecting surface B, Bd b. What is the frequency of the reflected wave as heard by a detector mounted on and moving with sound source A, JAd ?

9. A plane seismic wave, travelling vertically downwards in a rock of density 2200 kg m-3 with seismic velocity 2000 m s-1, is incident on the horizontal top surface of a rock layer of density 2400 kg m-3 and seismic velocity 3300 m s-1. (a) What are the amplitude ratios of the transmitted and reflected waves? (b) What fraction of the energy of the incident wave is transmitted into the lower medium?

A boat produces water waves as it sails along a river. You notice that 13 waves hit the bank in 5.4 seconds. If distance between successive wave crests is 3.9 centimeters, how far would these waves travel in 31 seconds. Express your answer in centimeters to at least 3 significant figures.

A geological disturbance in San Andreas fault generated a seismic wave that was detected in Phoenix, AZ, approximately 1000 km from the epicenter. If such waves travel at an average speed of 6.5 km/s, what would be the time-lag between the disturbance and the detection? How does this speed compare with that of sound waves in air at a day temperature of 23°C? 2.6 min, vseismic/ Vsound 19 O 2.6 min, vseismie/ Vsound 26 O 2.9 min, vseismie/ Vsound 29 O 3.2 min, vseismic/ Vsound 21

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The WCCO AM radio transmitter has a power of 49800 W. You measure the intensity of the signal to be 8×10−6 W/m^2. How far are you from the tower? (in km)(a) 7.89×101 km(b) 2.23×101 km(c) 4.45×101 km(d) 1.98×106 km(e) 8.90×101 km

Imagine you are at a location where some incident light source provides light at an intensity of 25 W/m^2. Now you move 5 time closer to the light source (aka your distance is 1/5 its initial value). What is the intensity of the light at this new location

One fine spring day, the Mayor attends a game at Yankee Stadium. In order to honor him, the announcer commands all 60,000 fans to send a “good old fashioned wave around the stadium.” By rising and sitting in succession, a familiar flurry does indeed make its way through the crowds of people. People watch the theatrics at home on their tv’s and internet feeds. Question: Is it scientifically accurate to refer to this human phenomenon as an example of wave motion? Why or not. Be specific and thorough.