Chapter 1, Problem 1.90CP

Completed Pass. The football team at Enormous State University (ESU) uses vector displacements to record its plays, with the origin taken to be the position of the ball before the play starts. In a certain pass play, the receiver starts at $1.0\hat{i}-\text{ 5}\text{.0}\hat{j}$, where the units are yards, $\hat{i}$ is to the right, and $\hat{j}$ is downfield. Subsequent displacements of the receiver are +9.0 $\hat{i}$ (he is in motion before the snap), +11.0 $\hat{j}$ (breaks downfield), −6.0 $\hat{i}$ + 4.0 $\hat{j}$ (zigs), and $12.0\hat{i}\text{ + 18}\text{.0}\hat{j}$ (zags). Meanwhile, the quarterback has dropped straight back to a position −7.0 $\hat{j}$. How far and in which direction must the quarterback throw the ball? (Like the coach, you will be well advised to diagram the situation before solving this numerically.)