Suppose an elephant has a mass of 2850 kg. show answer No Attempt How fast, in meters per second, does the elephant need to move to have the same kinetic energy as a 77-kg sprinter running at 7.5 m/s

When oxygen reacts with hydrogen, it has the capacity to release 29 kilojoules of energy. inside a fuel cell, oxygen reacts with hydrogen to produce 23 kilojoules of useful energy. the rest of the energy is lost as heat. what's the efficiency percentage of the fuel cell?