A motor-driven conveyor belt moves a crate of mass \(M\) at a constant speed \(v\) along a horizontal track. The coefficient of kinetic friction between the crate and the track is \(\mu\). To maintain this constant speed, the motor must supply a power \(P_1\). The crate is replaced with a larger crate of mass \(2M\) and the speed of the conveyor belt is increased to a constant speed of \(3v\). If the coefficient of kinetic friction remains the same, which of the following is the best estimate for the power \(P_2\) now supplied by the motor?