An electric toy car with a mass of #8 kg# is powered by a motor with a voltage of #9 V# and a current supply of #4 A#. How long will it take for the toy car to accelerate from rest to #8/3 m/s#?
The kinetic energy into the car is given by
The power from an electric circuit is given by
Mechanical power, meanwhile, is
The question is asking for
and, plugging in values that we know,