this is a question that i have been asked recently. if you have a small dc motor(Vrated=1.5V) and it is connected to battery (1.5v), the motor is supposed to run. however if you hold/blocked the rotating part it stops even though it is still connected to the battery.I know that voltage determine the rotating speed but in this case even with the 1.5V battery it stop rotating. the answer i came with is that the power delivered by the battery is not sufficient to overcome the blocking force. is this a valid reason or do you have another answer.