A student uses a scooter to travel around their local area in Brisbane. The scooter and rider together experience a gravitational force of 711 N. When travelling, the system of the scooter-plus-rider experiences resistive forces, opposite in direction to the motion. In a typical situation, these are a frictional force of 3 N (due to friction in the mechanisms of the scooter, and of the tyres with the road), and air resistance of 42 N. (a) What is the total of resistive forces acting on the scooter-plus-rider? (b) Explain why there must be some force in the forward direction for the scooter to accelerate forwards. Use one of Newton's laws of motion in your