Please help and don't ignore me =( haha?

Question

1. What is the period of a 560 Hz sound wave in air?

(speed of sound...medium is air----> speed=330 m/s)

2. Twenty waves pass by in 5 seconds. If the wavelength is 1/2 meter, how fast are the waves traveling?

even if you can answer one it would help, thanks =)

please show me how too!

Answer 1

"Period" is the amount of time it takes for a wave to pass. The period is the reciprocal of "frequency", commonly expressed in Hertz.

In problem # 1, the speed of sound in air is irrelevant. Just take the reciprocal of 560 Hz to obtain the frequency.

In problem # 2, twenty waves pass by in 5 seconds. That means 4 waves in 1 second. The length of 1 wave is 1/2 m. The length of 4 waves is 2 m. Therefore, it travels at 2 m/s.