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A body slides down on an inclined plane of inclination 45º from rest. The time takento cover a certain distance in the absence of fric-tion is half of the time taken to cover the same dis-tance in the presence of friction. Find the coeffi-cient of friction. |
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Answer» ) When there is no friction, From newton's SECOND law, F=ma ⇒mgsinθ=ma 1 ⇒a 1 =gsinθNow, as body starts from rest so INITIAL velocity (u)=0 m/s.Let, body travels 'X' distance in t 1 TIME,So from equation of MOTION, x=ut+ 21 at 2 ⇒x= 21 a 1 t 1 2 ⇒t 1 = a 1 2x = gsinθ2x Case (2) When there is friction, From newton's second law, F=ma ⇒mgsinθ−μmgcosθ=ma 2 ⇒a 2 =gsinθ−μgcosθNow, as body starts from rest so initial velocity (u)=0 m/s.Let, body travels 'x' distance in t 2 time,So from equation of motion, x=ut+ 21 at 2 ⇒x= 21 a 2t 22⇒t 2 = a 1 2x= gsinθ−μgcosθ2x It is given that t 2=2t1 So, gsinθ−μgcosθ2x =2gsinθ2x Now, substituting θ=45 and solving above equation we get, 1−μ1=2μ= 43=0.75pls mark me as brainliest answer pls... |
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