I was thinking about using a power drill to spin up a gyro. Let's say this gyro has two segments, a wide center and narrow ends. And its a perfectly rigid body. When the power drill is placed at the wide part, more torque is applied to the gyro and the gyro's angular acceleration is greater. When the power drill is placed at the narrow part, less torque is applied to the gyro and the gyro's angular acceleration is much less. In both cases the torque the gyro applies on the power drill should be the same. Then we have a dilemma, because in both cases the drill loses the same amount of energy, while in the first case the gyro has more rotational energy than in the second case. i must have overlooked something, but I can't seem to think of it now.