$165$ Two identical $40-$lb curling stones have diameters of $11$ in$.$ and may move freely on a sheet of ice. Stone B is at rest when stone A strikes it with a speed of $0\mathrm{.}5$m $/$ s$.($a$)$ Knowing that b$=5$ in and e$=0\mathrm{.}7,$ determine the velocity of each stone after impact in terms of $\_0.($b$)$ Show that if e$=1,$ the final velocities of the stones form a right angle for all values of b$.$