## Fundamentals of Physics Extended (10th Edition)

$v_{avg} = -0.7i + 1.4j -0.4k$
The initial position of the ion is $r = 5i - 6j + 2k$ and the final position is $r = -2i + 8j - 2k$. Velocity is defined as $\frac{\Delta x}{\Delta t}$ so we need to take the final position and subtract the initial position to find the change in x $\Delta x$ = (-2 -5) i + (8- -6)j + (-2 -2)k = -7i + 14j -4k $Since this occurred over 10s, we divide the vector by 10 and get$ v = -7/10 i + 14/10 j - 4/10k = -0.7i + 1.4j -0.4k \$