1.If an earthquake wave having a wavelength of 10.9 kmkm causes the ground to vibrate 13.0 times each minute, what is the speed of the wave?

2. The ocean floor is mapped by sending sound waves (sonar) downward and measuring the time it takes for their echo to return. From this information, the ocean depth can be calculated if one knows that sound travels at 1531 m/sm/s in seawater.

If a ship sends out sonar pulses and records their echo 3.38 ss later, how deep is the ocean floor at that point, assuming that the speed of sound is the same at all depths?