Disk P (inertia \(0.40 \mathrm{~kg}\) ) moves at an unknown velocity across a low-friction horizontal surface and collides with disk Q (inertia \(0.70 \mathrm{~kg}\) ), which is initially at rest. After the collision, the two (now slightly dented) disks move apart without spiming. Velocity information is provided in the initial and final top-view diagrams (Figure P10.64).

(a) What was the initial velocity of disk P? 

\((b)\) What fraction of the initial kinetic energy is converted during the collision?

Data from Figure P10.64

initial final P 1.4 m/s 20 Qat rest /50 (P not shown) 0.96 m/s