Hello I am not sure of the answers I gave. Can I have your opinion on them, please?
Q1: Three vectors $\vec u$, $\vec v$ and $\vec w$ of length 5, 12 and 15. If their sum gives $\vec 0$ what's the angle between the vectors $\vec u$ and $\vec v$ ?
Answer 1: 90 degrees
Q2: Two vectors $\vec u$, $\vec v$ of length 3 and 5, respectively, are added, and the result vector is perpendicular to $\vec u$. Give the angle that separates $\vec u$ and $\vec v$.
Answer 2 : 90 degrees
Thanks in advance for your help.