Starting from rest, a m $=2\mathrm{.}50$ kg block descends as the pulley rotates, unwinding the string. The pulley isa solid disk with a moment of inertia $0\mathrm{.}0840$ kg m and radius R $=0\mathrm{.}130$ m$.$ Assuming that the pulley's axle is frictionless and the string does not slip as it unwinds. The block and pulley start from rest, and the block falls a vertical distance of $1\mathrm{.}40$ m$.$a$)$ What is the block's linear speed?$=$b$)$ What is the pulley's angular speed?