The volume flow rate through the propeller of an airboat (a boat driven by a propeller moving air) is \(50 \mathrm{~m}^{3} / \mathrm{s}\). When the boat is docked, the speed of the slipstream behind the propeller at a location where the flow has returned atmospheric pressure is \(40 \mathrm{~m} / \mathrm{s}\). Determine

(a) the propeller diameter,

(b) the thrust produced when the boat is docked,

(c) the thrust produced at the same flow rate when the airboat is moving ahead at \(15 \mathrm{~m} / \mathrm{s}\), and

(d) the maximum speed of the boat.