## Calculus (3rd Edition)

If the speed were doubled, $r'=\langle 50, -70, 20 \rangle$. If the direction were reversed, $r'=\langle -25, 35, -10 \rangle$.
When the speed doubles, each component simply gets doubled, so $r'=2*\langle 25, -25, 10 \rangle = \langle 50, -70, 20 \rangle$. When the direction gets reversed, each component simply gets multiplied by -1, so $r'=-1*\langle 25, -25, 10 \rangle = \langle -25, 35, -10 \rangle$.