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Why there two propellers in a helicopter...

Why there two propellers in a helicopter ?

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If the helicopter had only one propeller, then due to conservation of angular momentum, the helicopter itself would turn in the opposite direction.
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PRADEEP-SYSTEMS OF PARTICLES AND ROTATIONAL MOTION-SHORT ANSWER QUESTIONS
  1. In which of the following cases shown Fig. it is most difficult to rot...

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  2. In first figure a meter stick, half of which is wood and the other hal...

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  3. Two circular discs A and B of equal masses and thicknesses. But are ma...

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  4. The radius of gyration of an uniform rod of length L about an axis pas...

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  5. Why there two propellers in a helicopter ?

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

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  7. Using expressisions for power and kinetic energy of rotational motion,...

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  8. A thin uniform circular disc of mass M and radius R is rotating in a h...

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  9. Is angular momentum of a system always conserved ?

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  10. A flywheel is revolving with a constant angular velocity. A chip of it...

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  11. Why are not able to rotate a wheel by pulling or pushing along its rad...

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  12. Explain why the speed of a whirl wind in a tornado is alarmingly high ...

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  13. State the two theorems of moment of inertia.

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  14. Explain the physical significance of moment of inertia and radius of g...

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  15. Obtain expression for K.E. of rolling motion.

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  16. State the laws of rotational motion.

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  17. The vector sum of a system of non-collinear forces acting on a rigid b...

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  18. A wheel in uniform motion about an axis passing through its centr...

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  19. A door is hinged at one and is free to rotate about a vertical axis [F...

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  20. (n - 1) equal point masses each of mass m are placed at the vertices o...

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