Difficulty: Easy
Correct Answer: a vector quantity
Explanation:
Introduction / Context:
Velocity is central to kinematics and dynamics. Distinguishing it from speed and understanding its directional nature are essential for correctly applying Newton’s laws and for resolving motions into components.
Given Data / Assumptions:
Concept / Approach:
A physical quantity that requires both magnitude and direction for complete specification is a vector. Velocity fits this definition: it specifies how fast and in what direction position is changing with time (v = dr/dt). Scalars like speed retain only magnitude, losing directional information.
Step-by-Step Solution:
Verification / Alternative check:
Vector addition rules apply to velocity (e.g., relative velocity problems). Component-wise, v = v_x i + v_y j (+ v_z k), confirming vector nature.
Why Other Options Are Wrong:
Common Pitfalls:
Interchanging “speed” and “velocity”; overlooking directional changes in circular motion where speed can be constant but velocity is not.
Final Answer:
a vector quantity
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