Dois carros, a e b, móveis se em uma estrada retilínea com volocidade constante,vª =20m/s e v=18 m/s , respectivamente. O carro A ,está, inicialmente, 500m atrás do carro B . Quanto tempo o carro A levará para alcançar o carro B

t = 250 s = 4.167 s

Explanation:

Carro A

x = x₀+v*t

⇒  x = 0 + 20*t  

⇒  x = 20*t   (i)

Carro B

x = x₀+v*t

⇒  x = 500 + 18*t    (ii)

Se as equações são as mesmas, verifica-se  (i) = (ii)

20*t = 500 + 18*t

⇒  20*t - 18*t = 500

⇒  2*t = 500

⇒  t = 250 s = 4.167 s

b. amplitude

Explanation:

There are two types of intereference:

- Constructive interference: it occurs when two waves of same frequency meet at a point in phase - this means , the crest of one wave meets with the crest of the other wave. When this occurs, the resultant wave has an amplitude which is equal to the sum of the amplitudes of the two waves.

- Destructive interference: it occurs when two waves of same frequency meet at a point in opposite phase - this means , the crest of one wave meets with the trough of the other wave. When this occurs, the resultant wave has an amplitude which is equal to the difference between the amplitudes of the two waves.

When interference occurs, the other factors of the waves (period, frequency and wavelength) do not change.