Q$.4$ Calculate the time required to machine a workpiece $180$ mm long, $70$ mm diameter to $172$ mm long, $50$ mm diameter. The workpiece rotates at $540$ rpm $,$ feed is $0\mathrm{.}25m\frac{m}{r}ev$ and maximum depth of cut is $2$ mm $.$ Assume approach and over$-$travel distance each as $5$ mm for turning operation as well as for facing operation.

$[8]$