Really how to select the wattage of the motor as I'm stuck with that. I came across several formulae, yet still unable to do it so.
Vehicle Mass = 120Kg
Load Mass = 100Kg (max)
Front tyre = 8" x 2
Back Tyre = 12" x 2
Tyre material = Polyurethane
Dimension = 25" x 35"
Speed = 9.3km/hr
They told that,
coeffient of rolling friction for PU = 0.2-0.7
coeffient of drag = 0.04 ( for oval shaped bodies)
density in aerodynamics force = density of air = 1.225
By following attached calculations I've got 4KW, yet with two - 0.5KW DC brushed motors itself it is working. I just want to know how it is possible!!