This problem revolves around the concept of conservation of angular momentum. Here’s how to approach the solution:

1. Angular Momentum Conservation Principle: The conservation of angular momentum states that if there is no external torque acting on a rotating system, its angular momentum remains constant. Mathematically, this is expressed as: $I_1 \omega_1 = I_2 \omega_2$ where $I$ is the moment of inertia and $\omega$ is the angular velocity.

2. Moment of Inertia and Angular Velocity Relationship: The moment of inertia, $I$, depends on how mass is distributed relative to the axis of rotation. When Student A pulls his arms in (reducing the distance of the weights from his body), he decreases the moment of inertia $I$ because the mass is now closer to the axis of rotation.

3. Effect on Angular Velocity: Since angular momentum $L = I \omega$ is conserved, a decrease in $I$ must be compensated by an increase in $\omega$. Therefore, as Student A pulls his arms in, his angular velocity $\omega$ increases to keep the product $I \omega$ constant.

4. Conclusion: When Student A brings the weights closer to his body, his angular velocity $\omega$ increases due to the decrease in his moment of inertia $I$. This effect is why we observe a faster spin in scenarios where a rotating object reduces its moment of inertia.

Would you like further details or have any questions?

Here are five related questions to explore this topic further:

1. What are real-life applications of the conservation of angular momentum?
2. How does the distribution of mass affect the moment of inertia in various shapes?
3. Can you describe a scenario where angular momentum is not conserved?
4. What are the differences in moment of inertia between a figure skater spinning with arms extended versus arms folded?
5. How does angular velocity change if external torque is introduced?

Tip: Remember, reducing the distance of mass from the axis of rotation always decreases the moment of inertia and typically increases rotational speed if no external torque is applied.