Final answer:
The question addresses the torque exerted on a bicycle wheel by a string and its effect on the wheel's angular momentum.
Step-by-step explanation:
The question is focused on determining the torque exerted on a wheel by a string as the wheel's speed increases. Torque refers to the rotational force applied to an object that causes it to rotate. In the case of a bicycle wheel, when a cyclist pedals harder or changes to a higher gear, this results in an increased torque application to the rear wheel, which in turn causes a change in the wheel's angular momentum.
In order to find the change in angular momentum, we would likely need to know the initial and final torques that are being exerted, the mass of the bicycle and cyclist, the radius of the bicycle wheel, and the time over which the torques are applied. The relationship between torque (τ) and angular momentum (L) is described by the equation τ = dL/dt, which shows that the rate of change of angular momentum is directly proportional to the applied torque.