(Solved):   A model of a person's arm is used for ergonomics studies. Distances are \( r_{A B}=35 \mat ...

 

A model of a person's arm is used for ergonomics studies. Distances are \( r_{A B}=35 \mathrm{~cm}, r_{B C}=28 \mathrm{~cm} \), and \( r_{C D}=19 \mathrm{~cm} \). NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Express \( \vec{r} \) AD using polar vector representation, measuring orientation positive counterclockwise from the right-hand horizontal direction. (Round the final answers to four decimal places. Include a minus sign if necessary.) The polar representation of the resultant vector is \( \vec{r}_{A D}= \) \( \mathrm{cm} @+ \)