Answer the following questions related to scalar and vector projection of one vector on another.
a. (i) Define the scalar projection (also called the component) of a vector a on a non-zero vector b.
b. (ii) Define the vector component (vector projection) of a along b.
c. (iii) Explain, with a labelled diagram, how the sign (positive, negative or zero) of the scalar projection depends on the angle between a and b. Support your explanation with one numerical example of two three-dimensional vectors of your choice.