The question asks about the direction of the acceleration vector $\vec{a}$ for an object moving along a curved path.

The correct answer is c: "vuông góc với vectơ vận tốc $\vec{v}$" (perpendicular to the velocity vector).

Explanation: In circular or curved motion, the acceleration vector can be broken down into two components:

1. Centripetal acceleration: Always points towards the center of the curve (perpendicular to the velocity vector).
2. Tangential acceleration: Aligned with the change in speed along the curve (parallel or anti-parallel to the velocity).

For uniform circular motion (where speed is constant), the total acceleration is purely centripetal and thus always perpendicular to the velocity vector $\vec{v}$.

Would you like more details or have any other questions?

Here are 5 related questions to expand on the topic:

1. What is the difference between tangential and centripetal acceleration?
2. How do you calculate the magnitude of centripetal acceleration?
3. What is the role of velocity in uniform circular motion?
4. How does acceleration behave in non-uniform circular motion?
5. What happens to the direction of velocity and acceleration in elliptical orbits?

Tip: In uniform circular motion, speed remains constant, but the velocity changes due to its direction changing, which causes the object to experience acceleration.