9. A figure skater with outstretched arms spins with an initial rotation rate of 1.0 rev every 1.2 s. She can increase her rotation speed by bringing her arms close to her body. Suppose her final rotation rate is 3.0 rev every 1.2 s. Find her moment of inertia with her arms close to her body if her moment of inertia with outstretched arms is 5.0 kg-m2. (Answer: I = 1.7 kg m²)

9. A figure skater with outstretched arms spins with an initial rotation rate of 1.0 rev every 1.2 s. She can increase her rotation speed by bringing her arms close to her body. Suppose her final rotation rate is 3.0 rev every 1.2 s. Find her moment of inertia with her arms close to her body if her moment of inertia with outstretched arms is 5.0 kg-m2. (Answer: I = 1.7 kg m²)

University Physics Volume 1

18th Edition

ISBN:9781938168277

Author:William Moebs, Samuel J. Ling, Jeff Sanny

Publisher:William Moebs, Samuel J. Ling, Jeff Sanny

Chapter11: Angular Momentum

Section: Chapter Questions

Problem 72P: An ice skater is preparing for a jump with turns and has his arms extended. His moment of inertia is...

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Concept explainers

Angular speed, acceleration and displacement

Angular acceleration is defined as the rate of change in angular velocity with respect to time. It has both magnitude and direction. So, it is a vector quantity.

Angular Position

Before diving into angular position, one should understand the basics of position and its importance along with usage in day-to-day life. When one talks of position, it’s always relative with respect to some other object. For example, position of earth with respect to sun, position of school with respect to house, etc. Angular position is the rotational analogue of linear position.

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9. A figure skater with outstretched arms spins with an initial rotation rate of 1.0 rev every 1.2 s. She can
increase her rotation speed by bringing her arms close to her body. Suppose her final rotation rate is 3.0 rev
every 1.2 s. Find her moment of inertia with her arms close to her body if her moment of inertia with
outstretched arms is 5.0 kg-m?. (Answer: I = 1.7 kg · m²)

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