An oxygen gas is flowing through a 10m circular tube length with a radius of 16cm. Oxygen concentrations in the pipe ends are 30 kg/m^3 and 10 kg/m^3. The diffusion constant of the oxygen at 20 ° C is 1.8 x 10^-5 m^2/s. (a) Calculate the diffusion flow rate (b) How many kilograms of oxygen will flow through this tube in 15 minutes? (c) What is the oxygen concentration 2m away from the end of the tube where there is high concentration? (d) How long will it take 100 kg of oxygen to travel this tube?

Amerry-go-round of radius r, shown in the figure, is rotating at constant angular speed. the friction in its bearings is so small that it can be ignored. a sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. the sandbag does not slip or roll upon contact with the merry-go-round. how would you rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round from largest to smallest. a) m = 10kg, r = 0.25r b) m = 20kg, r = 0.25r c) m = 10kg, r = 0.50r d) m = 10kg, r = 1.0r e) m = 15kg, r = 0.75r f) m = 40kg, r = 0.25r