A multi plate clutch having effective diameter $250$mm and $150$mm has to transmit $60$kW at $1200$ rpm$.$ The end thrust is $4\mathrm{.}5$ kN and coefficient of friction is $0\mathrm{.}08$ calculate the $$number of plates assuming $($i$)$ Uniform wear and $($ii$)$ uniform pressure distribution on the $$plates$.$