I am confused between scalars and vectors, how does magnitude and direction make a difference ?

Can someone please help me in understanding this concept. I am not able to figure out myself. Please provide some example if possible.

- Nupur Pandey asked 2 years ago
- last edited 2 years ago

**Scalars:-**

Scalar quantities are those quantities which require only the magnitude for their complete specifications. Physical quantities which can be completely specified by aÂ number and unit, and therefore have theÂ magnitude only, are scalars. Some physical quantities which are scalar are mass, length, time, energy, volume, density, temperature, electric charge, electric potential etc. These examples obey the algebraic law of addition.

**Vectors:-Â **

Vector quantities are those quantities which require magnitude as well as direction for their complete specifications. Vectors are physical quantities, which besidesÂ having both magnitude and direction also obey the law of geometrical addition.Â (The law of geometrical addition, i.e. the law of triangular addition and law of parallelogram are discussed later in this chapter). Some physical quantities, which are vectors are displacement, velocity, acceleration, force, electric intensity, magnetic intensity, magnetic moment etc. Vector quantities cannot, in general, be added in algebraically.

In case you still have doubt please refer to:Â http://www.askiitians.com/iit-jee-physics/general-physics/scalars-and-vectors.aspx

- Radhika Tanika answered 2 years ago

The simplest explanation I can tell you is that of temperature. We associate a magnitude with temperature, (ie how hot it is), but no sense of direction. We do not say it is 30 degrees celsius due west, or north. Hence temperature is a “scalar” quantity, which has only a sense of magnitude, and not direction.

The best example of a vector I can give is velocity. When an object is moving, it is with respect to some frame of reference. When we think of a car moving, it is always moving in some direction. Along with its direction, the car also has some speed, ie how fast it is moving. Thus velocity has a notion of both magnitude, as well as direction.

Hope that cleared any doubts!

- Aniket Rege answered 2 years ago

**Vectors** have magnitude **and** direction, **scalars** only have magnitude. The fact that magnitude occurs for both **scalars and vectors** can lead to some confusion. There are some quantities, like speed, which have **very special** definitions for scientists. By definition, speed is the **scalar** magnitude of a velocity **vector**.

Please read here for clarity: https://www.grc.nasa.gov/www/k-12/airplane/**vectors**.html

- Shraddha Goel answered 1 year ago

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