1. The problem statement, all variables and given/known data A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 30.08 above the horizontal. The car accelerates uniformly to a speed of 2.20 m/s in 12.0 s and then continues at constant speed. (a) What power must the winch motor provide when the car is moving at constant speed? (b) What maximum power must the winch motor provide? (c) What total energy has transferred out of the motor by work by the time the car moves off the end of the track, which is of length 1 250 m? 2. Relevant equations 3. The attempt at a solution I actually can get the answer but I just don't understand th The way I calculate it is that add part 2 and part 3 together and divide them by 12 and then add part 1 into the answer. I understand why word done by acceleration have to be divided by 12 (to convert it to power), but I just don't understand why I need to do the same thing for KE, if I divide it by 12, then it will become the power required to accelerate the object from 0 m/s to 2.2 m/s, which is exactly the same thing as having the word done by acceleration divided by 12. So, why do I need to divide KE by 12? Or the entire thing is just plain wrong? Thanks!