A $200$ mm wide strip with an initial thickness of $10$ mm is fed through a rolling mill with two powered rolls, each of radius $300$ mm$.$ The workpiece thickness is reduced to $7$ mm in a single pass. The roll speed is $60$ revolutions per minute $($RPM$),$ and the coefficient of friction between the rolls and the workpiece is $0\mathrm{.}15.$ The flow curve of the material is defined by K $=250$ MPa and n $=0\mathrm{.}2.$Calculate:$1.$ The draft in the rolling operation$\mathrm{.}2.$ The contact length between the rolls and the workpiece$\mathrm{.}3.$ The rolling force required$\mathrm{.}4.$ The power needed to perform the rolling operation.