Question

A car travels 20 Km north. It then turns around and travels 30 Km south. what is the car's displacement?

Answer 1

10Km South. Displacement is the total distance the subject is from the starting point.

Answer 2

10 km south

Step-by-step explanation:

The two displacements of the car are vectors, so they have a magnitude and a direction.

The first displacement is 20 km north.

The second displacement is 30 km south.

Since the two displacements are along the same direction (north-south), we can calculate their resultant simply adding them, but taking one of the two with a negative sign (because they are opposite). If we take south as positive direction, and north as negative direction, the resultant displacement becomes

`D=-20 km +30 km=+10 km`

and since it has positive sign, the direction is south.