Lesson 1: Vector and Scalar

Video Lesson

Competencies (MLC)

Dear Learner,

At the end of this lesson, you will be able to:

• Define scalar and vector quantities;
• Describe the difference between vector and scalar quantities;
• List some scalar and vector quantities.

Brainstorming Questions

• What is the fundamental difference between a vector and a scalar?
• Can a scalar ever be converted into a vector, or vice versa? If so, how?

Key Terms and Concepts

Physical Quantity

Physical quantities are classified into Scalars and vectors, that are used in physics and math. (physical quantity is a property of a material or system that can be quantified by measurement)

Scalar quantity:

Scalar quantities are quantities that are described only by a magnitude. They do not have a direction of action. For instance, it makes perfectly good sense to say that the length of an object is 1.42 m or that the mass of an object is 12.21 kg. You do not have to add anything to the description of length or mass. Similarly, the statement that the density of water is 1000 kg/m³ is a complete description of density. Quantities that can be specified in this simple and straightforward way are called scalar quantities. Time, distance, speed, length, volume, temperature, energy and power are other examples of scalar quantities.

Vector quantity:

A vector quantity is defined as the physical quantity that has both directions as well as magnitude. A simple example is velocity. The statement that the velocity of a train is 100 km/h does not make much sense unless you also tell the direction in the train is moving Force is another such quantity. Displacement, acceleration, momentum, impulse, weight and electric field strength are other examples of vector quantities.

Exercises

1. What is the difference between vector and scalar?
2. What is the relationship of both?
3. Which of the following physical quantities are vectors and which aren’t: force, temperature, volume, velocity, age, weight?