Scalar vs Vector

A scalar has magnitude only: a single number with units. Examples: mass (kg), temperature (K), energy (J), electric potential (V), time (s), charge (C).

A vector has both magnitude and direction. In 3-D, a vector has three components transforming together under rotations. Examples: velocity (m/s with direction), force (N), momentum (kg·m/s), electric field (V/m), acceleration (m/s²).

Scalars add by ordinary arithmetic. Vectors add component-wise, equivalently by the parallelogram rule. The dot product of two vectors is a scalar; the cross product (in 3-D) is a vector. Higher-rank objects — tensors — generalise scalars (rank-0) and vectors (rank-1) and appear throughout relativity and continuum mechanics.

Recent research on this topic from arXiv

Preprints and papers indexed on arXiv.org. Links open the public abstract pages.

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