Final answer:
For a bicycle to maintain stability while exiting a corner, it must keep a straight line with forces acting to align gravity with ground force, involving friction and centripetal force for balance.
Step-by-step explanation:
The bicycle must maintain a straight line in order to achieve platform stability during an exit of a corner. This is a principle in physics, where the stability of a bicyclist, or any similar system, relies on both the angle of lean and the forces acting upon it when turning. When turning, the force of gravity acting on the bicycle must align with the force exerted by the ground to maintain balance and stability. The force on the wheels is resolved into two perpendicular components: friction parallel to the ground that supplies the centripetal force, and the vertical normal force that equals the system's weight. These forces interact to keep the bicyclist stable as they lean into the turn at the correct angle, ensuring the net external force on the system—the centripetal force—keeps them moving in a circular path without falling over.