Question

a block slide down an incline plane of angle30 degree with an acceleration of g/4. find the coefficient of kinetic friction

Answer 1

Normal force acting on block = mgcos30

force along the direction of motion = mgsin30
= mg/2

frictional force acting on block = uN
= umgcos30
= umg√3/2

By applying Newton's 2nd law of motion :
mg/2 - umg√3/2 = ma

here a = g/4

(1-√3u)/2 = 1/4
2-2√3u = 1
u = 1/(2√3)
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