Section 2:
1) Recalling that torque is work per radian, find how much work is done by a force of 300 N applied to a sprocket of radius 6 cm (not m)on a bicycle wheel when the wheel makes 3 turns. Assume the wheel is attached to a bicycle with a rider on it with a total mass of 100 kg, and the the bike was at rest to begin with. How fast is the bike going after three turns of the wheel ( note sprocket and wheel turn together - the sprocket is the gear on a bike's rear wheel)? Use the relationship between work done and KE to figure this out.
2) If all the wheel's mass of 1 kg is at the rim how much rotational KE does the wheel have at the speed you just found? Is it important compared to the total KE so that you need to revise your calculation or is it negligible?
Show all work.
Section 3: Recall that angular acceleration, alpha, is torque/I. If a force (all tangential) of twenty Newtons is applied to the end of a .4 m long crank attached to a disk with a moment of inertia (I) of .5 kg m^2, what is the resulting alpha? What is omega after two seconds? Repeat the problem only with a force of 80 N.
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