In one model of jogging, the energy expended is assumed to go into accelerating and decelerating the legs. If the mass of the leg is m and the running speed is v, the energy needed to accelerate the leg from rest to v is ½ mv² and the same energy is needed to decelerate the leg back to rest for the next stride. Thus, the energy required for each stride is mv². Assume that the mass of a man's leg is 10 kg and that he runs at a speed of 3 m/s with 1 m between one footfall and the next. Therefore, the energy he must provide to his legs in each second is 3 × mv². Calculate the rate of the man's energy expenditure using this model and assuming that his muscles have an efficiency of 25%.