There are two inclined surface of equal length (L) and same angle of inclination 45^ with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes 2 times as much time to slide down on rough surface than on the smooth surface. The coefficient of kinetic friction ( _

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There are two inclined surface of equal length (L) and same angle of inclination 45^ with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes 2 times as much time to slide down on rough surface than on the smooth surface. The coefficient of kinetic friction ( _k ) between the object and the rough surface is close to :

Quantrex Academy · Accepted Answer

Correct answer: D. 0.75

aligned & L= 1 2 a_S t_S^2= 1 2 a_R t_R^2 \ & ( t_ s t_R )^2= a_R a_ S \ & ( 1 2 )^2= g - _k g g \ & 1 4 = 45^ - _k 45^ 45^ \ & 1 4 = ( 1 2 ) ( 1 2 ) ( 1- _k 1 ) \ & 1 4 =1- _k _k=1- 1 4 = 3 4 =0.75 aligned

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