FIGURE 11-48 Problem 78. 79. Competitive ice skaters commonly perform single, double, and triple axel jumps in which they rotate 1, 2 , and 3 revolutions, respectively, about a vertical axis while airborne. For all these jumps, a typical skater remains airborne for about 0.70 s. Suppose a skater leaves the ground in an "open" position (e.g., arms outstretched) with moment of inertia Io and rotational frequency fo 1.2 rev/s, main- taining this position for 0.10 s. The skater then assumes a "closed" position (arms brought closer) with moment of inertia I, acquiring a rotational frequency f, which is maintained for 0.50 s. Finally, the skater immediately returns to the "open" position for 0.10 s until landing (see Fig. 11-49). (a) Why is angular momentum conserved during the skater's jump? Negleet air resistance. (b) Determine the minimum rotational frequency f during the flight's middle section for the skater to successfully complete a single and a triple axel. (c) Show that, according to this model, a skater must be able to reduce his or her moment of inertia in midflight by a factor of about 2 and 5 in order to complete a single and triple axel, respectively. %3D
FIGURE 11-48 Problem 78. 79. Competitive ice skaters commonly perform single, double, and triple axel jumps in which they rotate 1, 2 , and 3 revolutions, respectively, about a vertical axis while airborne. For all these jumps, a typical skater remains airborne for about 0.70 s. Suppose a skater leaves the ground in an "open" position (e.g., arms outstretched) with moment of inertia Io and rotational frequency fo 1.2 rev/s, main- taining this position for 0.10 s. The skater then assumes a "closed" position (arms brought closer) with moment of inertia I, acquiring a rotational frequency f, which is maintained for 0.50 s. Finally, the skater immediately returns to the "open" position for 0.10 s until landing (see Fig. 11-49). (a) Why is angular momentum conserved during the skater's jump? Negleet air resistance. (b) Determine the minimum rotational frequency f during the flight's middle section for the skater to successfully complete a single and a triple axel. (c) Show that, according to this model, a skater must be able to reduce his or her moment of inertia in midflight by a factor of about 2 and 5 in order to complete a single and triple axel, respectively. %3D
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
Related questions
Question
![(a)
FIGURE 11-48 Problem 78.
79. Competitive ice skaters commonly perform single, double,
and triple axel jumps in which they rotate 1,23, and
3 revolutions, respectively, about a vertical axis while airborne.
For all these jumps, a typical skater remains airborne for
about 0.70 s. Suppose a skater leaves the ground in an
"open" position (e.g., arms outstretched) with moment of
inertia Io and rotational frequency fo = 1.2 rev/s, main-
taining this position for 0.10 s. The skater then assumes a
"closed" position (arms brought closer) with moment of
inertia I, acquiring a rotational frequency f, which is
maintained for 0.50 s. Finally, the skater immediately returns
to the "open" position for 0.10 s until landing (see Fig. 11-49).
(a) Why is angular momentum conserved during the skater's
jump? Neglect air resistance. (b) Determine the minimum
rotational frequency f during the flight's middle section for
the skater to successfully complete a single and a triple axel.
(c) Show that, according to this model, a skater must be able
to reduce his or her moment of inertia in midflight by a
factor of about 2 and 5 in order to complete a single and
triple axel, respectively.
fo
| fo
0.1s
0.5 s
0.1 s
FIGURE 11-49
Problem 79.
General Problems
309](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fda1bb534-4c29-4f5a-b750-1e08cb95b058%2Ffae453ff-06a0-4180-90ba-da6abc4e74e2%2Ftp466wbk_processed.jpeg&w=3840&q=75)
Transcribed Image Text:(a)
FIGURE 11-48 Problem 78.
79. Competitive ice skaters commonly perform single, double,
and triple axel jumps in which they rotate 1,23, and
3 revolutions, respectively, about a vertical axis while airborne.
For all these jumps, a typical skater remains airborne for
about 0.70 s. Suppose a skater leaves the ground in an
"open" position (e.g., arms outstretched) with moment of
inertia Io and rotational frequency fo = 1.2 rev/s, main-
taining this position for 0.10 s. The skater then assumes a
"closed" position (arms brought closer) with moment of
inertia I, acquiring a rotational frequency f, which is
maintained for 0.50 s. Finally, the skater immediately returns
to the "open" position for 0.10 s until landing (see Fig. 11-49).
(a) Why is angular momentum conserved during the skater's
jump? Neglect air resistance. (b) Determine the minimum
rotational frequency f during the flight's middle section for
the skater to successfully complete a single and a triple axel.
(c) Show that, according to this model, a skater must be able
to reduce his or her moment of inertia in midflight by a
factor of about 2 and 5 in order to complete a single and
triple axel, respectively.
fo
| fo
0.1s
0.5 s
0.1 s
FIGURE 11-49
Problem 79.
General Problems
309
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