Disk P (inertia (0.40 mathrm{~kg}) ) moves at an unknown velocity across a low-friction horizontal surface and

Question:

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