I want to calculate the mechanical power I can output continuously on a stationary bike. The good news is I have the power vs. speed curve available for the given bike, the question is how much power does it take to accelerate from one speed to another? If I know it takes 250W at 20mph and 275W at 21mph, how many watts does it take to accelerate from 20mph to 21mph in 1 second? I think I need to know something about the inertia of the system but that could be calibrated if I just knew the equations. Also how would the equations change if it was not a stationary bike assuming riding in a vacuum on flat ground?