# The time taken by a body to slide down a rough 45 degrees inclined plane is twice that required to slide down a smooth 45 degrees inclined plane.the coefficent of friction between the object and rough plane is given by :a. 1/3b. 3/4c. root 3/4d. root 4/3rply pls...

Grade:11

## 3 Answers

Badiuddin askIITians.ismu Expert
148 Points
13 years ago

hi rohan bhatia

accelarion along the downward direction of wedge

a1=(mgsin45-μmgcos45)/m

=(1-μ)g/√2

let total time taken is t

s=0*t +.5(a1)t^2

when wedge is frictionles

then acceleration

a2=g/√2

s=0*t/2 +.5(a2)*(t/2)^2

equate both value of s

μ=3/4

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Badiuddin

manoj jangra
8 Points
13 years ago

hey ans is 3/4

when you compare

let x be length of the wedge

X = 1/2 gsinθ t2           for smooth plane

X = 1/2 (gsinθ-μcosθ)4t2    foe rough plane

you will get ams 3/4

rohan bhatia
18 Points
13 years ago

thank u very much sir for solving my problems.

q. a block of mass m is resting on a wedge of angle θ with what minimum acceleration a should the wedge move so that the mass m falls freely ?

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