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A particle is projected up a rough inclined plane of inclination `theta` and friction coefficient `mu`. If the time of ascent is half of the time of descent, the friction coefficient `mu` is equal toA. `(3)/(4) tan theta`B. `(3)/(5) tan theta`C. `(4)/(5) tan theta`D. `(1)/(2) tan theta` |
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Answer» Correct Answer - B Upward motion : Retardation : `a_(1) = g sin theta + mu g cos theta , t_(1) = t` Downward motion : Acceleration : `a_(2) = g sin theta - mu g cos theta , t_(2) = 2t` `s = (1)/(2) a_(1) t_(2)^(2) = (1)/(2) a_(2) t_(2)^(2) rArr a_(1) (t)^(2) = a_(2) ( 2t)^(2)` `a_(1) = 4 a_(2)` `g sin theta + mu g cos theta = 4 ( g sin theta - mu g cos theta)` `mu = (3)/(5) tan theta` |
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