Talk:Exercise bike

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Client comments on the Mechanical Analysis

This useful mechanical analysis focuses on the moment of inertia of heavy metal wheel and braking friction, which are critical to the design of the exercise bike. Here is my comments about the analysis:

• Should the radius of the disc be equal to the inner radius of the ring? Please verify it.
• The calculation for the flywheel rotating speed change by brake seems not correct: 28.27J=1/2*0.646*^ω2. So ω=9.35 rad/sec = 89.3 rpm. Please verify your calculation.
• According to energy conservation, the energy input by a biker pedaling is equal to the brake friction energy plus the energy going into flywheel (with other friction ignored): E_BIKER = E_BRAKE + ΔE_FLYWHEEL. If a biker is pedaling the bike with constant angular velocity (steady state), there is no energy in/out the flywheel and ΔE_FLYWHEEL=0. The analysis in your case seems to assume a biker stops pedaling and the flywheel rotation is slowing down due to brake energy consumption. In this case, the angular velocity of flywheel is changing and you have to use integration to do the right calculation.
• The moment of inertia of the 5kg lighter flywheel is not given in the analysis. Please double check.
• It is suggested to add a figure of flywheel rpm versus calorie consumption can be added into the analysis results. It will be useful information to the exercise bike users.