5 Relative to an origin \(O\), the position vectors of the points \(A\) and \(B\) are given by
$$\overrightarrow { O A } = \left( \begin{array} { c }
p - 6
2 p - 6
1
\end{array} \right) \quad \text { and } \quad \overrightarrow { O B } = \left( \begin{array} { c }
4 - 2 p
p
2
\end{array} \right)$$
where \(p\) is a constant.
- For the case where \(O A\) is perpendicular to \(O B\), find the value of \(p\).
- For the case where \(O A B\) is a straight line, find the vectors \(\overrightarrow { O A }\) and \(\overrightarrow { O B }\). Find also the length of the line \(O A\).