The Spinning Figure Skater. The outstretched hands and arms of a figure skater p

Question

The Spinning Figure Skater. The outstretched hands and arms of a figure skater preparing for a spin can be considered a slender rod pivoting about an axis through its center. When the skater's hands and arms are brought in and wrapped around his body to execute the spin, the hands and arms can be considered a thin-walled, hollow cylinder. His hands and arms have a combined mass 8.0 kg. When outstretched, they span 2.1 m; when wrapped, they form a cylinder of radius 27 cm. The moment of inertia about the rotation axis of the remainder of his body is constant and equal to 0.40 kg·m2. If his original angular speed is 0.40 rev/s, what is his final angular speed?
rev/s ?

Explanation / Answer

Ii = 1/12 (8.0kg)(2.1)^2+0.40kgm^2

= 3.34 kg m^2

If = (8.0)*(0.27)^2 +0.40

= 0.9832 kg m^2

Li = Lf = Iiwi = Ifwf

wf 3.34 kg m^2/0.9832 kg m^2 * 0.40 rev/s = 1.35 rev/s

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.