What is the period of a wave (in seconds) that has a velocity of 1 km/s and a wavelength of 5 meters?

What is the period of a wave (in seconds) that has a velocity of 1 km/s and a wavelength of 5 meters?

1. What is the period of a wave (in seconds) that has a velocity of 1 km/s and a wavelength of 5 meters? (Answer must be number only-no units or exponents)

2. What is the frequency of that wave in Hz? (Answer must be just a number – no units.)

3. What is the wavelength in meters of a 1000 Hz sound wave? (Number answer only)

4.Sound travels at different speed in different gases.  At room temperature, a 400 Hz sound wave has a wavelength of 2.52 m in helium.  What is the speed of sound in helium in m/s? (Number answer only)