A vector has both magnitude and direction. Does it mean that anything that has magnitude and direction is necessarily a vector ? The rotation of a body can be specified by the direction of the axis of rotation, and the angle of rotation about the axis. Does that make any rotation a vector ?

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Solution

A vector has both magnitude and direction, but any physical quantity having both magnitude and direction need not be a vector. A physical quantity can be considered as a vector if it follows the law of vector addition. For example, electric current is a scalar quantity despite having both magnitude and direction.

No, the rotation of a body about an axis is not a vector quantity since it does not follow the law of vector addition. However, the infinitesimally small rotation is a vector quantity as it obeys the law of vectors addition.

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