Question

A car travels 20 km South, then turns and travels 30 km East? What is the total displacement?

Answer 1

Answer:

Explanation:36.05 km

Given

First car travels $r_1=20\ km$ South

then turns and travels $r_2=30\ km$ east

Suppose south as negative y axis and east as positive x axis

So, $r_1=-20\hat{j}$

$r_2=30\hat{i}$

Displacement is the shortest between initial and final point

Dispalcement$=r=r_1+r_2$

Displacement$=-20\hat{j}+30\hat{i}$

Displacement$=30\hat{i}-20\hat{j}$

Magnitude $=\sqrt{30^2+(-20)^2}$

Magnitude$=36.05\ km$