Question

A truck travelling due north at $20m{s}^{-1}$ turns west and travels at the same speed. Find the change in its velocity.

Answer 1

Initial velocity of truck $=0\uparrow +20\hat{j}$ m/s

Final velocity of truck $=20\uparrow +0\hat{j}$ m/s

Change in velocity $=(20\uparrow +0\hat{j})-(0\uparrow +20\hat{j})$

$=20\uparrow -20\hat{j}$

$\left|V\right|=\sqrt{{\left(20\right)}^2+{\left(20\right)}^2}=20\sqrt{2}$ m/s.