Scalar and Vector Products: Matrix & Differences

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Jasmine Grover

Education Journalist | Study Abroad Strategy Lead

Scalar products and vector products are two kinds of techniques for combining two separate vectors.

  • They are commonly used in the fields of physics and astronomy. 
  • The scalar product between two vectors can be described as a combination of the magnitudes of both vectors 
  • And the inverse cosine of the angle that lies between them.

Key terms: Scalar Product, Vector Product, Magnitude, Matrix, Product, Multiplication, Mathematical Operation, Determinants, Dimensions.


Scalar Product

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"Scalar products can be determined by calculating the element of one vector that follows the path of another vector and multiplying it by the magnitude of another vector." 

  • Scalar product or dot product is a mathematical operation that requires two equal length series of integers and produces a single value.
  • The scalar product is also known as the dot product or inner product, and ensures that scalar multiplication is constantly symbolised by a dot.

When the identical vectors are written as unit vectors i, j, and k along their axis x, y, and z, the scalar product is as follows:

\(\vec{A}\vec{B} = \vec{A}_x\vec{B}_x + \vec{A}_y\vec{B}_y + \vec{A}_z\vec{B}_z\)

Where,

\(\vec{A} = \vec{A}_x \hat{i}+ \vec{A}_y\hat{j} + \vec{A}_z\hat{k}\)

\(\vec{B} = \vec{B}_x \hat{i}+ \vec{B}_y\hat{j} + \vec{B}_z\hat{k}\)

Matrix representation of scalar product

Rather than the unit vectors mentioned above, vectors can be represented as row or column matrices. When we consider vectors to be column matrices of their x, y, and z elements, then the vectors' transforms are row matrices.

\(\vec{A} = [\vec{A}_x\vec{A}_y \vec{A}_z ]\)

\(\vec{B} = [\vec{B}_x\vec{B}_y \vec{B}_z ]\)

The matrix that is the combination of these two matrices will provide us the scalar result of the two matrix structures that is the total of the respective geographical elements of the given two vectors; the number that results is going to be the scalar product of vector A and vector B.

Application of Scalar Product

There are numerous applications for the scalar product, including designing games and engineering. These are:

  1. Find the shortest path to a location. 
  2. Determine the total force applied in a specific direction.
  3. Matrix multiplication in linear algebra
  4. Utilising the formula cos θ = (x.y) / (|x| |y|) get the angle across two vectors.
  5. Estimating the quantity of power which solar panels can generate.

Read More: Bayes Theorem Formula


Vector Product

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The magnitude vector multiplication of two provided vectors is calculated by multiplying the magnitudes of the vectors by the sine of the angle across two. 

It can be stated as follows:

  • A vector multiplication or cross product is a binary operation performed on two vectors in three different directions.
  • The magnitude of the vector product can be expressed as follows:

\(\vec{A} \times \vec{B}\) = AB sinθ

Vector Products Represented by Determinants

Scalar products have a few distinguishing characteristics that make them helpful in the present moment. Initially in terms of scalar products, the path of the angle throughout the formula has no importance for the two vectors.It can only be evaluated from one vector to another because cosθ = cos(-θ) = cosθ (2π−θ). 

  • If the angle inside a scalar product is more than 90° and below or equal to 180°, the product has a value that is negative. 
  • As a result, the scalar products' equation for maths is 90° < θ < =180°.
  • Vector products, on the other hand, contain two distinguishing characteristics that set them apart from scalar products. 
  • To begin, generally vector products rely on the right handed screw rule to determine the correct and necessary direction in real time. 
  • Most crucially, the vector products are non-communicative, as demonstrated by the equation of mathematics b x a = – axb.
  • Vector also includes a structure with three dimensions based on the dot product gateway. 
  • Ultimately, a vector product can be changed because it stays comparable when the path of a vector alters in immediate effect.

Read More: Complex Numbers and Quadratic Equations


Important Concept of Scalar and Vector Product

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The important concepts of Scalar & Vector are mentioned:

  • It is practical to enhance one vector by another, but not to separate it. 
  • There are two kinds of vector elements which are frequently employed in physics and engineering. 
  • Scalar multiplication of two vectors is one type of multiplication. As the title suggests, the product of the scalars of two vectors yields a number (a scalar).
  • The relationship between energy and work is defined using scalar products. 
  • As an instance, the work done on an object by a force (a vector) while causing its displacement can be described as the scalar product of the force vector and the displacement vector (a vector).
  • Vector multiplication is an unusual type of multiplication. As the title suggests, the vector product of two vectors yields a vector. 
  • Vector products are employed for establishing derived vector variables.
  • In the definition of assignments, a vector variable termed torque has been defined as the product of a vector of a force given (a vector) 
  • Its displacement from the pivot to the force (a vector). 

Read More: Geometric Mean (G.M.)


Difference between Scalar and Vector product

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The various difference between Scalar product and Vector product are as follows:

Parameters Scalar product Vector product
Meaning A scalar quantity contains merely magnitude and lacks any direction. A vector quantity includes both magnitude as well as direction.
Alterations It varies with the magnitude of the alterations. It varies depending on whether they change direction, magnitude, or both.
Quantities Each scalar quantity has a single dimension. Vector quantities can be one dimensional, two dimensional, or three dimensional.
Resolution Scalar quantities are unable to resolve since their values are the same irrespective of direction. The sine or cosine of the nearby sector can be used to resolve a vector quantity in any direction.
Operations Any mathematical action performed on two or more scalar quantities will yield only a scalar. However, if a scalar is multiplied by a vector, the output is a vector. The outcome of the mathematical operations performed on two or more vectors might be scalar or vector. As an instance, the dots in the product of two vectors that are combined yields a scalar, whereas the cross product, summation, or subtraction of two vectors yields a vector.
Expression They are represented by basic letters, such as V for velocity. They are indicated by using boldface letters, such as V for velocity, or by placing a pointed object over the word.
Measurement Easy Difficult
Example A vehicle is travelling at 30 kilometres per hour. A vehicle is travelling east at 30 kilometres per hour.

Also Read:


Things to Remember

  • A scalar quantity is one which possesses magnitude but does not have direction and is frequently expressed by a value that includes a unit. 
  • A scalar quantity is something like the distance travelled by a car in a single hour or the mass of a bag.
  • Scalar products are mathematical operations that require separate equal length numerical series which produce only one product at a time.
  • Vector multiplication, also known as cross product, is a binary computation that is done on two vectors in three separate directions.
  • The Vector Quantity is a variable that fluctuates with magnitude and direction, such as power, movement, popularity, acceleration, and velocity.
  • It is indicated by an integer and a point at the top (a) or by a unit cap, such as a.
  • The product of the value for each of the vectors and the cosine of the angle between them is used to compute the scalar product of two vectors.

Previous Year Questions

  1. Extraction of metal from the ore cassiterite involves...[JEE Advanced 2011]
  2. Commonly used vectors for human genome sequencing are...[NEET UG 2014]
  3. Interfascicular cambium and cork cambium are formed due to​..
  4. Pneumotaxic centre is present in​...[UP CPMT 2007]
  5. Reaction of HBr with propene in the presence of peroxide gives….[NEET UG 2004]
  6. Assuming the expression for the pressure exerted by the gas on the walls of the container, it can be shown that pressure is...[MHT CET 2016]
  7. Which among the following is the strongest acid?...[TS EAMCET 2017]
  8. Isopropyl alcohol on oxidation forms​..
  9. A vector is not changed if​..
  10. Which of the following arrangements does not represent the correct order of the property stated against it?...[JEE Main 2013]

Sample Questions

 

Ques. What is the value of the product of two vectors with an angle of 60 degrees between them, \(\vec{A}\) = 2\(\hat{i}\) + 3\(\hat{j}\) and \(\vec{B}\) = 3\(\hat{i}\) - 4\(\hat{j}\)? (2 marks)

Ans. We begin by determining the magnitudes of the two vectors:

A = √22 + 32 = √4 + 9 = √13

YB = √32 + (-4) = √9 + 16 = √25 = 5

The cross product A × B = AB sinθ = 5*√13*Sin 60° = 5* √13* √3/2

Ques. Describe the basics of a scalar quantity. (3 marks)

Ans. Scalars are physical quantities with only one magnitude in the physical sciences. Its functionalities are unaffected by their position or introductions, and their magnitude completely denotes them. Scalar examples include density, energy, mass, time, volume, and speed. Force, velocity, and acceleration are complex quantities with direction and magnitude (vectors). Scalars are represented by real numbers that are almost always positive and almost never negative. When a body goes in the opposite direction that the force exerts, the work done on it is a negative amount. Scalars can be determined using fundamental algebraic rules.

Ques. Describe the importance of vectors in physics. (3 marks)

Ans. Vectors are extremely important in physics. Vectors may indicate a body's acceleration and velocity, as well as its forces. Many additional physical quantities can be thought of as vectors. Despite the fact that the majority of them do not denote distance, their directions and magnitude can still be denoted by the direction of an arrow and length. The graphical representation of physical vectors is determined by the coordinate system used to describe them.

Ques. What is the correlation between Scalar and Vector products? (2 marks)

Ans. Both the scalar and vector products are extensively used in engineering and physics because they can be used after mathematical multiplication. In a sense, scalar products are based on vectors in real-time, therefore the relationship that develops between them is based on work and energy.

Ques. How do the Scalar and Vector products appear? (2 marks)

Ans. Scalar products are referred to as dot products, while vector products are referred to as cross products due to their distinguishing properties. As a result, the scalar products are represented by a dot (.) and the vector products by a cross (x).

Ques. How do you describe the scalar product of two vectors as a matrix? (2 marks)

Ans. Instead of encoding vectors as unit vectors, it is sometimes more convenient and easier to represent them as row or column matrices. By transposing the x, y, and z coordinates of a vector as a column matrix, we can obtain row matrices. As a result of this, we may write: [Xx Xy Xz] = XT.

Ques. What are the real time applications of vectors? (1 mark)

Ans. Vectors are required for describing direction and magnitude via additional rules. When it comes to defining velocity, it is crucial in delineating the magnitude of speed in real time.

Ques. Define the followings: (3 marks)
Scalar product
Vector product

Ans. Scalar product: The scalar product of two vectors can be described as the sum of their dimensions and the cosine of their angles. The dot product or inner product are other names for the scalar product.

Vector product: A vector product, sometimes known as a cross product, is a binary computation based on two vectors in all three dimensions.

Ques. Describe the importance of mathematical quantities in physics. (3 marks)

Ans. Physics is nature's mathematical representation. Almost all principles and concepts have a mathematical foundation. There are numerous cases where mathematical tools are required to deconstruct and explain topics. Physics is founded on the mathematical side of physical concepts. Any complex subject can be reduced to clear sets of laws, formulae, or equations using mathematics. The motion of bodies can be described using a combination of necessary words. However, language cannot explain the complicated mechanics underpinning motion, and only mathematical approaches can reliably understand and explain these complex notions. 

Ques. What are the most common vector examples? (1 mark)

Ans. Vectors include linear momentum, displacement, acceleration, momentum, angular velocity, force, angular velocity, polarisation, and electric field.

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CBSE CLASS XII Related Questions

  • 1.
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    • 2.
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      • 3.
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            • AC can be transmitted economically over long distances.
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          • 5.
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              • 6.
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                CBSE CLASS XII Previous Year Papers

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