2. On average, both arms and hands together account for 13% of aperson's mass, while the head is 7.0%and the trunk and legs accountfor 80%. We can model a spinning skater with her arms outstretchedas a vertical cylinder (head, trunk, and legs) with two soliduniform rods (arms and hands) extended horizontally.

Suppose a 68.0 kg skater is 1.50 m tall, has arms that are each64.0 cm long (including the hands), and a trunk that can be modeledas being 32.0 cm in diameter. If the skater is initially spinningat 72.0 rpm with her arms outstretched, what will her angularvelocity ?2 be (in rpm) after she pulls in her arms and they are ather sides parallel to her trunk? Assume that friction between theskater and the ice is negligble.

w2=

3. A child's top is held in place upright on a frictionlesssurface. The axle has a radius of ?=2.96 mm Two strings are wrappedaround the axle, and the top is set spinning by applying ?=3.40 Nof constant tension to each string. If it takes 0.440 s for thestring to unwind, how much angular momentum does the top acquire?Assume that the strings do not slip as the tension is applied.

angular momentum:__________kgâ‹…m2s

Point P is located on the outer surface of the top, a distanceâ„Ž=31.0 mm above the ground. The angle that the outer surface of thetop makes with the rotation axis of the top is ?=27.0 . If thefinal tangential speed ?t of point P is 1.85 m/s , what is thetop's moment of inertia?

moment of inertia: ______________kgâ‹…m2