Question

Vectors can only be used to add velocities that are parallel to each other. Is this true? I can't find it in my book.

Answer 1

in one word, no.

vectors have components, 2, 3, 4 and even more components. \( \left( \begin{array}{c} v_1 \\ v_2 \\ v_3 \end{array} \right) \) is a 3-dimensional vector with three components. You can only add vectors of the same dimension because you add each component separately.

if you've got parallel vectors you might be able to omit the vector character. Lets say the 2nd and 3rd component of both vectors you want to add are 0. in that case you dont have to worry about the vector and you can just add the components that are not 0