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)

#1

Wavelength = 13 km

it vibrates 10 times each minute

so the frequency is defined by the number of vibrations per second

now the speed of wave is defined as

so here velocity of wave is 2.2 km/s

#2

Intensity of wave is directly proportional to the square of its amplitude

so we can say

k = constant

so if amplitude is doubled then its intensity will be increased by its square

so intensity is 4 times

Por essa razão, é correto admitir, como fazem todos os autores, que a história da humanidade só se inicia como uso da escrita. A História é um saber científico e, portanto, não muda. Podemos comprovar que aquilo que …

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