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Two discs of moments of inertia I(1) and...

Two discs of moments of inertia `I_(1) and I_(2)` about their respective axes (normal to the disc and passing through the centre), and rotating with angular speeds `ω_(1) and ω_(2)` are brought into contact face to face with their axes of rotation coincident. (a) What is the angular speed of the two-disc system? (b) Show that the kinetic energy of the combined system is less than the sum of the initial kinetic energies of the two discs. How do you account for this loss in energy? Take `omega_(1)neomega_(2)`

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Two disc of moments of inertia I_(1)andI_(2) about their respective axes (normal to the disc and passing through the centre), and rotating with angular speeds omega_(1)andomega_(2) are brought into contact face to face with their axes of rotation coincident. (a) What is the angular speed of the two-disc system? (b) Show that the kinetic energy of the combined system is less than the sum of the initial kinetic energies of the two discs. How do you account for this loss in energy? Take omega_(1)neomega_(2) .

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A round disc of moment of inertia I_(2) about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia I_(1) rotating with an angular velocity omega about the same axis. The final angular velocity of the combination of disc is.............

(a) A child stands at the centre of a turntable with his two arms outstretched. The turntable is set rotating with an angular speed of 40 rev/min. How much is the angular speed of the child if he folds his hands back and thereby reduces his moment of inertia to 2/5 times the initial value ? Assume that the turntable rotates without friction. (b) Show that the child’s new kinetic energy of rotation is more than the initial kinetic energy of rotation. How do you account for this increase in kinetic energy?

(a) A child stands at the centre of a turntable with his two arms outstretched. The turntable is set rotating with an angular speed of 40 rev/min. How much is the angular speed of the child if he folds his hands back and thereby reduces his moment of inertia to (2)/(5) times the initial value? Assume that the turntable rotates without friction. (b) Show that the child.s new kinetic energy of rotation is more than the initial kinetic energy of rotation. How do you account for this increase in kinetic energy?

NCERT GUJARATI-SYSTEMS OF PARTICLES AND ROTATIONAL MOTION-EXERCISES
  1. (a) A child stands at the centre of a turntable with his two arms outs...

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  2. A rope of negligible mass is wound round a hollow cylinder of mass 3 k...

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  3. To maintain a rotor at a uniform angular speed of 200 rad s-1, an engi...

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  4. From a uniform disk of radius R, a circular hole of radius R/2 is cut ...

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  5. A metre stick is balanced on a knife edge at its centre. When two coin...

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  6. A solid sphere rolls down two different inclined planes of the same he...

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  7. A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal floor ...

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  8. The oxygen molecule has a mass of 5.30 × 10^(-26) kg and a moment of i...

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  9. A solid cylinder rolls up an inclined plane of angle of inclination 30...

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  10. As shown in Fig.7.40, the two sides of a step ladder BA and CA are 1.6...

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  11. A man stands on a rotating platform, with his arms stretched horizonta...

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  12. A bullet of mass 10 g and speed 500 m/s is fired into a door and gets ...

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  13. Two discs of moments of inertia I(1) and I(2) about their respective a...

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  14. (a) Prove the theorem of perpendicular axes. (b) Prove the theorem o...

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  15. Prove the result that the velocity v of translation of a rolling body ...

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  16. A disc rotating about its axis with angular speed ω(o) is placed light...

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  17. Explain why friction is necessary to make the disc in Fig. 7.41 roll i...

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  18. A solid disc and a ring, both of radius 10 cm are placed on a horizont...

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  19. A cylinder of mass 10 kg and radius 15 cm is rolling perfectly on a pl...

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  20. Separation of Motion of a system of particles into motion of the centr...

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