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)
Conduction could be the way in which heat is transferred through a sausage to get it up to cooked temperature. convection could be the air around the barbecue and the smell of the barbecue being carried on thermal convection currents. hope this is honest enough