May 2019 la. [1 mark] A girl rides a bicycle that is powered by an electric motor. A battery transfers energy to the electric motor. The emf of the battery is 16 V and it can deliver a charge of 43 kC when discharging completely from a full charge. The maximum speed of the girl on a horizontal road is 7.0 m s" with energy from the battery alone. The maximum distance that the girl can travel under these conditions is 20 km. Show that the time taken for the battery to discharge is about 3 x 10' s. 1b. [2 marks/Deduce that the average power output of the battery is about 240 W. 1c. [2 marks] Friction and air resistance act on the bicycle and the girl when they move. Assume that all the energy is transferred from the battery to the electric motor. Determine the total average resistive force that acts on the bicycle and the girl. (ans: 34N)