A student sits on a freely rotating stool holding two dumbbells, each of mass 3.09 kg (see figure below). When his arms are extended horizontally (Figure a), the dumbbells are 0.99 m from the axis of rotation and the student rotates with an angular speed of 0.749 rad/s. The moment of inertia of the student plus stool is 2.61 kg. m² and is assumed to be constant. The student pulls the dumbbells inward horizontally to a position 0.301 m from the rotation axis (Figure b). (a) Find the new angular speed of the student. rad/s (b) Find the kinetic energy of the rotating system before and after he pulls the dumbbells inward. Kbefore- K after = J ]

A student sits on a freely rotating stool holding two dumbbells, each of mass 3.09 kg (see figure below). When his arms are extended horizontally (Figure a), the dumbbells are 0.99 m from the axis of rotation and the student rotates with an angular speed of 0.749 rad/s. The moment of inertia of the student plus stool is 2.61 kg. m² and is assumed to be constant. The student pulls the dumbbells inward horizontally to a position 0.301 m from the rotation axis (Figure b). (a) Find the new angular speed of the student. rad/s (b) Find the kinetic energy of the rotating system before and after he pulls the dumbbells inward. Kbefore- K after = J ]

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter13: Rotation Ii: A Conservation Approach

Section: Chapter Questions

Problem 45PQ: A thin rod of length 2.65 m and mass 13.7 kg is rotated at anangular speed of 3.89 rad/s around an...

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