Hello. I'm trying to find the torque required of an electric vehicle to pull a 1000kg trolley on four Nylon Wheels on smooth concrete. The trolley fully supports its own weight. The vehicle has 2 rubber drive wheels of Radius( r = .125m). Now I'm not sure if am on the right track because i cant find much information on Rolling resistance. Using Fr = Crr * N to find the rolling resistive force. Where Fr = Rolling resistance force Crr = coefficient of rolling resistance N = Normal force Rolling resistance of trolley Assuming Crr = .004 N = 1000kg * 9.81 m/s^2 Ft= (.004*9810) = 39.24 rolling resistance of vehicle Fv = (45kg * 9.81 m/S^2 * .08) Fv = 35.316 Ftotal = Fv +Ft Ftotal = 35.316 + 39.24 = 74.6N So if I use the equation for toque T = F * r T = 74.6 * .125 T = 9.32 N.m This should give me the minimum required torque to get the trolley and vehicle rolling on a smooth horizontal surface. Yes/No? Also if my system were to reach maximum velocity of 5km/h (1.389m/s) how do I find the torque needed. Regards tcitizen PS I've tried to include as much information as possible.