3. Given that the point \(A\) has position vector \(3 \mathbf { i } - 7 \mathbf { j }\) and the point \(B\) has position vector \(8 \mathbf { i } + 3 \mathbf { j }\),
- find the vector \(\overrightarrow { A B }\)
- Find \(| \overrightarrow { A B } |\). Give your answer as a simplified surd.