A toy car has a mass of 120g, including two 1.5V batteries connected in series. Suppose the motor that drives the car is 80% efficient (i.e., 80% of the electric energy goes to the drive wheels, 20% is dissipated as heat) and that friction and air resistance are negligible. How much charge passes through the batteries during the time it takes the car to accelerate from rest to 1.5 m/s? I thought i might be using these equations somehow. Not entirely sure though. P=IE I=[tex]\Delta[/tex]Q/[tex]\Delta[/tex]t ? I'm really having a hard time knowing where to begin. Any hints or thought provoking questions would help. I suppose i need to find out the amount of time it takes for the car to accelerate to that velocity first but i really have no idea how to begin.