A smooth block is released at rest on a 45° incline and then slides a distance d. The time taken to slide is n times as much to slide on rough incline than on a smooth incline. The coefficient of friction is
(1) μk =1-/n2
(2) μk=√(1-1/n2)
(3) μs=1-1/n2
(4) =√(1-1/n2)
