Everything Science Grade 10

CHAPTER 21. MOTION IN ONE DIMENSION 21.2

but displacement has a direction.
Kevin walks to school with Komal and after school walks back home. What is Kevin’s
displacement and what distance did he cover? For this calculation we use Kevin’s house as
the reference point. Let’s take towards the school as the positive direction.

Distance (D) = path travelled

= 500m+ 500m

= 1000m

Displacement(∆~x) = ~xf −~xi

= 0m+ 0m

= 0m

It is possible to have a displacement of 0 m and a distance that is not 0 m. This happens
whenever you end at the same point you started.

Differences between distance and displacement

The differences between distance and displacement can be summarised as:

Distance Displacement

1. depends on the path 1. independent of path taken


2. always positive 2. can be positive or negative


3. is a scalar 3. is a vector

Exercise 21 - 2

1. Use this figure to answer the following questions.

100 m 100 m 100 m 100 m 100 m 100 m

School Komal Kholo Kosma Kogis Kevin Shop

a. Kogis walks to Kosma’s house and then to school, what is her distance

and displacement?

b. Kholo walks to Kosma’s house and then to school, what is her dis-

tance and displacement?

c. Komal walks to the shop and then to school, what is his distance and

displacement?

d. What reference point did you use for each of the above questions?

2. You stand at the front door of your house (displacement,∆~x= 0m). The

street is 10 m away from the front door. You walk to the street and back

again.

Physics: Mechanics 395