Final answer:
The student's question regarding the velocity of a billiard ball after a collision requires applying principles of conservation of momentum and possibly, for other questions, conservation of energy.
Step-by-step explanation:
The question asked deals with the topic of conservation of momentum in collisions, particularly within a Physics context. Essentially, to find the velocity of ball 2 after the impact with ball 1, we must apply the principle that the total momentum before and after the collision remains constant since no external forces are involved.
Applying the conservation of momentum for a two-dimensional collision, we can set up equations for the conservation of momentum in both the horizontal and vertical directions. Given that the two balls have equal masses and one ball comes to rest after the collision, we can infer the speed and direction of the second ball after impact. The final velocity of the second ball is determined by solving the system of equations formed by the momentum conservation principles.
To answer other questions about recoil velocity or projectile motion, one would again use the principles of conservation of momentum and energy, considering all given data points like masses, speeds, and angles.