TOPIC 1.3 SCALAR QUANTITY VS VECTOR QUANTITY
From previous subtopic, we have learnt about some quantities, like distance, mass, speed, etc. Now look at the following situation:
We might have some experiences of losing our ways especially when we are in an unfamiliar place. For example, we may ask where is the washroom? Where can I find food shop?
Definitely, we might hear the answers like:
"Walk 200 meters to the right."
"It is 300 meters away from that building."
From the answers, we could see the similarities:
a) Both answers have values, or we call values.
b) Both answers have directions, or locations relative to others.
Hence, we know that there must have some quantities not only with magnitude but also with direction.
At the end of subtopic, you are able to:
- define scalar and vector quantities.
- give examples of scalar and vector quantities.
There are two types of physical quantities:
a) Scalar quantity
- Physical quantities with only magnitude.
- For example: temperature, distance, speed, volume, area, mass.
b) Vector quantity
- Physical quantities with both magnitude and direction.
- For example: displacement, velocity, acceleration, force, weight.
QUESTION!!!!
What is the difference between distance and displacement? Why do we have two different names for length?
Remember? From the situation of asking direction, we need both magnitude and direction. For example, can you imagine if people tell you to walk 200 meters in order to reach toilet? You will feel confused as you don't know which direction to go. Hence, displacement is the distance between two points in particular direction.
How about distance? Sometimes we don't have to know about the direction. For example, 100 m race in Olympics event. We only care about how far, since we know that the athletes are running in a straight line.
Watch this video to understand more:
(Not to worry, we will cover more in Chapter 2 about distance vs displacement, speed vs velocity)
Here is a summary of Chapter 1.3 Scalar Quantity vs Vector Quantity.
Next time we will learn about measurements.
Revision materials:
