Direction Cosines Model

Purpose

To aid in perception of the components of a three-dimensional vector.

Equipment

Direction cosines model, as photographed.

Suggestions

Emphasize that the angle between the vector and any axis is not the same as the angle between the axis and the projection of the vector onto a plane defined by two axes.

Images

a2-33

Description

An arbitrary vector in three-dimensional space is shown along with projections along the three orthogonal axes. Observe how the angles alpha, beta, gamma are defined.

References

(PIRA 1A40.10)