Final answer:
Initially, if an ice cube is at rest then its initial velocity is 0 m/s, which is relevant when considering momentum and kinematics in physics problems such as those involving ice hockey collisions. The correct option is 1.
Step-by-step explanation:
If an ice cube starts at rest at point a, then by definition, the initial velocity of the ice cube is 0 m/s. This is the velocity before any external forces act upon it, therefore, the correct answer to the student's question is option 1) 0 m/s.
In ice hockey, as well as in other physical systems, when an object is in a state of rest and has not yet been subjected to any net force that changes its state of motion, its initial velocity is always zero. The ice hockey examples you provided all involve concepts of momentum and kinematics, which follow the laws of classical mechanics outlined by Newton's laws of motion.
The initial velocities play a critical role in analyzing the outcomes of collisions or movements after the application of forces. Hence, 1 is the correct option.