European InterCity Express trains operate at speeds of up to \(280 \mathrm{~km} / \mathrm{hr}\). Suppose that a train is \(120 \mathrm{~m}\) long. Treat the sides and top of the train as a smooth flat plate \(9 \mathrm{~m}\) wide. When the train moves through still air at sea level, calculate the possible length of the laminar boundary layer and the thickness of this layer at its downstream end. What is the thickness of the boundary layer at the rear end of the train? What is the viscous drag force on the train and what power must be expended to overcome this resistance at maximum speed? At 50 percent of maximum?