Answer:
Explanation:36.05 km
Given
First car travels [tex]r_1=20\ km[/tex] South
then turns and travels [tex]r_2=30\ km[/tex] east
Suppose south as negative y axis and east as positive x axis
So, [tex]r_1=-20\hat{j}[/tex]
[tex]r_2=30\hat{i}[/tex]
Displacement is the shortest between initial and final point
Dispalcement[tex]=r=r_1+r_2[/tex]
Displacement[tex]=-20\hat{j}+30\hat{i}[/tex]
Displacement[tex]=30\hat{i}-20\hat{j}[/tex]
Magnitude [tex]=\sqrt{30^2+(-20)^2}[/tex]
Magnitude[tex]=36.05\ km[/tex]
