If an earthquake wave having a wavelength of 13 km caused the ground to vibrate 10 times each minute, what is the speed of the wave?
1.2 km/s
2.2 km/s
220 m/s
22 m/s
If the amplitude in a sound wave is doubled, by what factor does the intensity of the wave increase?
2
1
8
4(my choice)
period = 60/10 = 6 seconds
goes 13 km in 6 seconds
13/6 = 2.2 km/s
yes, 2^2 = 4
F = 10vib/min = 10vib/60s = 1/6 vib/s = Freq.
T = 1/F = 1/(1/6) = 6 s. = Period.
Wavelength = V*T= 13.
V * 6 = 13,
V = 2.2 km/s.
To calculate the speed of the earthquake wave, we can use the formula:
Speed (v) = Wavelength (λ) × Frequency (f)
Given that the wavelength is 13 km and the frequency is 10 times per minute, we need to convert the frequency to Hz (since speed is usually measured in m/s):
Frequency (f) = 10 times per minute × (1 minute / 60 seconds) = 0.1667 Hz
Now we can plug these values into the formula:
Speed (v) = 13 km × 0.1667 Hz = 2.1661 km/s
Rounding to the nearest tenth, the speed of the wave is approximately 2.2 km/s.
For the second question, doubling the amplitude of a sound wave would result in quadrupling the intensity of the wave.
Therefore, the correct answer is 4.
To determine the speed of the earthquake wave, we can use the formula:
Speed = Wavelength × Frequency
Given that the wavelength is 13 km and the frequency is 10 times per minute, we first convert the frequency to cycles per second (Hz).
Frequency = 10 times/minute
= 10/60 Hz
= 1/6 Hz
Now we can substitute the values into the formula:
Speed = 13 km × 1/6 Hz
= 13/6 km × 1000 m/km × 1/6 Hz
= 2200 m/s
Therefore, the speed of the earthquake wave is 2200 m/s.
For the second question, the intensity of a sound wave is directly proportional to the square of its amplitude.
If the amplitude is doubled, we need to calculate the factor by which the intensity increases.
Let's assume the initial intensity is I.
According to the question, if the amplitude is doubled, the new amplitude would be 2 times the initial amplitude.
Since intensity is proportional to the square of the amplitude, the new intensity would be (2^2 = 4) times the initial intensity.
So, by doubling the amplitude, the intensity of the wave increases by a factor of 4.
Therefore, the correct answer is 4.