Hi, I'm designing a gadget whereby I'm spinning a plastic propeller attached to a shaft which is attached to a 6V DC motor. I'm required to do a basic energy analysis of the set-up. The kinetic energy of the propeller is 0.5*I*w^2 (w=omega=angular velocity). Due to friction (air etc) then the motor will presumably have to supply energy to 'replenish' this lost energy. My questions are: 1. Is the energy supplied by the motor constant? Or is there an initial surge to get the propeller going, then a somewhat lesser energy supply to keep it going? 2. How do I relate this to time; i.e. how do I analysis power usage? Any ideas???