This will send you spinning for a while...

A meter rod, free to spin abt a stationary vertical axis passing through one of its ends is kept on a rough table of coeff. of friction .5, and spun with an initial angular velocity of 1 rad/sec.

Whats the time taken for it to stop rotating???




Now the rod is replaced by the following object:
A sector (pizza-share like) of a circle of radius 1m and of very small angular width..(say .5 degrees, which means you neglect it).
Again find the time....assume axis passes thru the would-be center of the circle..

Finally do the same for a meter rod whose linear mass density varies as the nth power of the distance from the axis.

7 comments:

  1. for the rod one I am getting t=4/(3g)
    g=acc. due to gravity

    bhaiya please check the previos posts also and post their solns like that of the repose theorem.

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  2. the general expression is
    (n+2)/(5(n+3))
    put n=0,n=1(for second part)
    to get the answer

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  3. ans of first is t=3/4g
    bhaiya plz tell tht tape vala ques (its really a good one)

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  4. for the first
    4/3g

    second

    3/2g

    third

    2(n+2)/(n+3)g

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  5. someone of you four is right.

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  6. I am also getting all answers the same as ankush.

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  7. bhaiya i substituted g as 10.
    mine and ankush's answers are the same

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