In: Physics
In this problem you will determine the amount of force a rider needs to exert on a bicycle pedal to accelerate at a rate of 1.0 m/s^2.
(c) Now consider the system consisting of the rear wheel. The system includes the sprocket (gear wheel) attached to it. Assume that the rear sprocket has a radius of 2.5 cm and neglible mass compared to the wheel. Assume that the rear wheel has the same mass, radius, and moment of inertia as the front wheel. The sprocket is driven by the bicycle chain. Assume that the tension in the upper portion of the bicycle chain is nonzero, neglect the tension in the lower portion of the chain. Write a free-body diagram for the system. By considering the torques on the system, find the tension in the chain.
(d) Now consider the system consisting of the crank, which means the front sprocket, and the pedals. The system is mounted on a frictionless axle. Assume that the pedals are a distance of 17 cm from the crack axle, that the front sprocket has a radius of 8.0 cm. Assume that the entire crank assembly has a moment of inertia 2.5 x 10^-2 kg m^2. Assume that the bike pedals are oriented horizontally, and that the rider is pushing straight downward on the forward pedal with a force F, with no force on the back pedal. Write a free-body diagram for the system. By considering the torques on the system, find the force F. Does your answer change if we neglect the moment of inertia of the crank?
(e) Is this a realistic force for a rider to exert on a bike pedal? If not, estimate the maximum acceleration you think is realistic for a bicycle.