Final answer:
To perform a left turn at highway speed on a motorcycle, the rider must pull back on the right handlebar initiating countersteering. This causes the motorcycle to lean to the left due to the conservation of angular momentum, allowing gravity and centrifugal forces to assist in the turn.
Step-by-step explanation:
When a motorcycle is in motion at highway speed, initiating a turn involves a counter-intuitive process known as countersteering. To execute a left turn, the rider must pull back lightly on the right handlebar. This action creates a torque on the motorcycle's front wheel, causing it to point slightly to the right. As a result, the motorcycle initially leans to the left due to the conservation of angular momentum. Once the lean is initiated, the bike will begin to turn in the same direction due to centrifugal forces and the shape of the tires, which are designed to facilitate this turn when the bike is leaning at an angle.
The phenomena that allow this to happen are rooted in the principles of physics, specifically Newton's laws of motion and the conservation of angular momentum. The bike's lean changes the direction of the force of gravity to the side, which, combined with the momentum, allows the motorcycle to make a smooth and stable turn.