Starting form the origin, a person walks 8km east during first day, and 5km west the next day. what is the net displacement of the person from the initial point in two days

The net displacement was 3 km

Explanation:

Displacement and Distance

Although they are similar concepts, there are a number of differences between distance and displacement. First of all, distance is a scalar magnitude, displacement is a vector. Distance is the sum of all individual lengths the object traveled on, regardless of their direction. Displacement is just the vectorial difference between the final and the initial positions.

We know the person walks 8 km east during the first day, and then 5 km west the next day. If we just added both values, we will compute the distance and conclude the person walked 13 Km in two days. But the question requires us to compute the displacement. We need the initial point and the final point. The initial point is the origin P(0).

On the first day, the person walked 8 km east, so his position was R(8). The second day he walked back 5 km west, so his final position was Q(3).

The net displacement was (3)-(0)=(3 km)