A yodeler yodels at a cliff 2000 m away. The sound of the echo returns in 9.8 s. If the wavelength of the sound wave is .85 m then what is the period of the sound wave?

Hey man, are you who I think you are? ... you used your student number on your account anyways im in your class :) guess who I am for free points. so the formula for period is Period=Wavelength/Velocity, so P=.85/velocity, to find velocity would be using the formula speed=distance/time, so the velocity is 2000/9.8 which is around 204.0816327 so back to period formula, P=.85m/204.08 which gives a period of .004165. But im not entire sure so you have to check that on your own. (gl guessing who I am. hehe)

Explanation: