Question

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

Answer 1

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
`=√(30^2+(-20)^2)`

Magnitude
`=36.05\ km`