# Use the figure and write the vector in terms of the other two vectors

Home Questions Tags Users Unanswered. Write a vector in terms of 2 other vectors Ask Question. Asked 4 years, 8 months ago. Active 4 years, 8 months ago.

Simplifying vector expressions

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Sponsored Links. Search for:. MathJax Mathematical equations are created by MathJax. Step by Step Explanation.A vector can be multiplied by another vector but may not be divided by another vector. There are two kinds of products of vectors used broadly in physics and engineering. One kind of multiplication is a scalar multiplication of two vectors.

Taking a scalar product of two vectors results in a number a scalaras its name indicates. Scalar products are used to define work and energy relations.

For example, the work that a force a vector performs on an object while causing its displacement a vector is defined as a scalar product of the force vector with the displacement vector. A quite different kind of multiplication is a vector multiplication of vectors. Taking a vector product of two vectors returns as a result a vector, as its name suggests.

Vector products are used to define other derived vector quantities. For example, in describing rotations, a vector quantity called torque is defined as a vector product of an applied force a vector and its distance from pivot to force a vector. It is important to distinguish between these two kinds of vector multiplications because the scalar product is a scalar quantity and a vector product is a vector quantity.

The scalar product is also called the dot product because of the dot notation that indicates it. The scalar product of a vector with itself is the square of its magnitude:.

### Math Insight

For the vectors given in Figure 2. In the Cartesian coordinate system, scalar products of the unit vector of an axis with other unit vectors of axes always vanish because these unit vectors are orthogonal:.

For unit vectors of the axes, Equation 2. We can use the commutative and distributive laws to derive various relations for vectors, such as expressing the dot product of two vectors in terms of their scalar components.

When the vectors in Equation 2. Since scalar products of two different unit vectors of axes give zero, and scalar products of unit vectors with themselves give one see Equation 2. Thus, the scalar product simplifies to.

We can use Equation 2. When we divide Equation 2. Substituting the scalar components into Equation 2. Finally, substituting everything into Equation 2. How much work is done by the first dog and by the second dog in Example 2.

The magnitude of the vector product is defined as. According to Equation 2. The anticommutative property means the vector product reverses the sign when the order of multiplication is reversed:. The corkscrew right-hand rule is a common mnemonic used to determine the direction of the vector product. As shown in Figure 2. The direction of the cross product is given by the progression of the corkscrew.

To loosen a rusty nut, a Find the magnitude and direction of the torque applied to the nut. The magnitude of this torque is. Physically, it means the wrench is most effective—giving us the best mechanical advantage—when we apply the force perpendicular to the wrench handle. In the latter case, the angle is negative because the graph in Figure 2. In this way, we obtain the solution without reference to the corkscrew rule. Similar to the dot product Equation 2.

The distributive property is applied frequently when vectors are expressed in their component forms, in terms of unit vectors of Cartesian axes.In a two-dimensional coordinate system, any vector can be broken into x -component and y -component. In the above figure, the components can be quickly read.

The trigonometric ratios give the relation between magnitude of the vector and the components of the vector. Using the Pythagorean Theorem in the right triangle with lengths v x and v y :. Case 1: Given components of a vector, find the magnitude and direction of the vector. Case 2: Given the magnitude and direction of a vector, find the components of the vector. Find the components of the vector.

Names of standardized tests are owned by the trademark holders and are not affiliated with Varsity Tutors LLC. Media outlet trademarks are owned by the respective media outlets and are not affiliated with Varsity Tutors. Varsity Tutors connects learners with experts. Instructors are independent contractors who tailor their services to each client, using their own style, methods and materials. Components of a Vector In a two-dimensional coordinate system, any vector can be broken into x -component and y -component.

The vector and its components form a right angled triangle as shown below. Use the following formulas in this case. Subjects Near Me. Download our free learning tools apps and test prep books.

Varsity Tutors does not have affiliation with universities mentioned on its website.Vectorin physicsa quantity that has both magnitude and direction. Although a vector has magnitude and direction, it does not have position. That is, as long as its length is not changed, a vector is not altered if it is displaced parallel to itself.

In contrast to vectors, ordinary quantities that have a magnitude but not a direction are called scalars. For example, displacementvelocityand acceleration are vector quantities, while speed the magnitude of velocitytime, and mass are scalars. To qualify as a vector, a quantity having magnitude and direction must also obey certain rules of combination. Geometrically, the vector sum can be visualized by placing the tail of vector B at the head of vector A and drawing vector C—starting from the tail of A and ending at the head of B—so that it completes the triangle.

### Components of a Vector

Quantities such as displacement and velocity have this property commutative lawbut there are quantities e. The other rules of vector manipulation are subtraction, multiplication by a scalar, scalar multiplication also known as the dot product or inner productvector multiplication also known as the cross productand differentiation. There is no operation that corresponds to dividing by a vector.

See vector analysis for a description of all of these rules. Although vectors are mathematically simple and extremely useful in discussing physics, they were not developed in their modern form until late in the 19th century, when Josiah Willard Gibbs and Oliver Heaviside of the United States and England, respectively each applied vector analysis in order to help express the new laws of electromagnetismproposed by James Clerk Maxwell. Vector Article Media Additional Info. The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree See Article History. One method of adding and subtracting vectors is to place their tails together and then supply two more sides to form a parallelogram. The vector from their tails to the opposite corner of the parallelogram is equal to the sum of the original vectors.

The vector between their heads starting from the vector being subtracted is equal to their difference. The ordinary, or dot, product of two vectors is simply a one-dimensional number, or scalar. In contrast, the cross product of two vectors results in another vector whose direction is orthogonal to both of the original vectors, as illustrated by the right-hand rule.

Get exclusive access to content from our First Edition with your subscription. Subscribe today. Learn More in these related Britannica articles:. Physicsscience that deals with the structure of matter and the interactions between the fundamental constituents of the observable universe. In the broadest sense, physics from the Greek physikos is concerned with all aspects of nature on both the macroscopic and submicroscopic levels.

Its scope of study encompasses not only…. Scalara physical quantity that is completely described by its magnitude; examples of scalars are volume, density, speed, energy, mass, and time. Other quantities, such as force and velocity, have both magnitude and direction and are called vectors.

Scalars are described by real numbers that are usually but not necessarily positive. Displacementin mechanics, distance moved by a particle or body in a specific direction. Particles and bodies are typically treated as point masses—that is, without loss of generality, bodies can be treated as though all of their mass is concentrated in a mathematical point.In the introduction to vectorswe discussed vectors without reference to any coordinate system.

By working with just the geometric definition of the magnitude and direction of vectors, we were able to define operations such as addition, subtraction, and multiplication by scalars. We also discussed the properties of these operation. Often a coordinate system is helpful because it can be easier to manipulate the coordinates of a vector rather than manipulating its magnitude and direction directly.

When we express a vector in a coordinate system, we identify a vector with a list of numbers, called coordinates or components, that specify the geometry of the vector in terms of the coordinate system. Here we will discuss the standard Cartesian coordinate systems in the plane and in three-dimensional space.

Using the Pythagorean Theorem, we can obtain an expression for the magnitude of a vector in terms of its components. Can you calculate the coordinates and the length of this vector?

To find the coordinates, translate the line segment one unit left and two units down. The below applet, repeated from the vector introductionallows you to explore the relationship between a vector's components and its magnitude.

The magnitude and direction of a vector. The two defining properties of a vector, magnitude and direction, are illustrated by a red bar and a green arrow, respectively. More information about applet. The vector operations we defined in the vector introduction are easy to express in terms of these coordinates. The below applet, also repeated from the vector introductionallows you to explore the relationship between the geometric definition of vector addition and the summation of vector components.

The sum of two vectors. You may have noticed that we use the same notation to denote a point and to denote a vector. We don't tend to emphasize any distinction between a point and a vector. You can think of a point as being represented by a vector whose tail is fixed at the origin. You'll have to figure out by context whether or not we are thinking of a vector as having its tail fixed at the origin.

A unit vector is a vector whose length is one. Here is one way to picture these axes. Stand near the corner of a room and look down at the point where the walls meet the floor. The negative part of each axis is on the opposite side of the origin, where the axes intersect. Three-dimensional Cartesian coordinate axes. A representation of the three axes of the three-dimensional Cartesian coordinate system.

The origin is the intersection of all the axes. The branch of each axis on the opposite side of the origin the unlabeled side is the negative part. You can drag the figure with the mouse to rotate it. If you do that, you will be living in a mathematical universe in which some formulas will differ by a minus sign from the formula in the universe we are using here.From the definition of the cross product the following relations between the vectors are apparent:.

The commutative law does not hold for cross product because:. Operations on Vectors. Vectors Definition. Vectors Cross Product. Vectors functions and derivation. Vectors Addition. Vector spherical cylindrical coordinates. Vectors Dot Product. Vectors definition. A vector V is represented in three dimentional space in terms of the sum of its three mutually perpendicular components.

Where i, j and k are the unit vector in the x, y and z directions respectively and has magnitude of one unit. The scalar magnitude of V is:. Let V be any vector except the 0 vector, the unit vector q in the direction of V is defined by:. Two vectors V and Q are said to be parallel or propotional when each vector is a scalar multiple of the other and neither is zero.

Vectors addition obey the following laws: Commutative law:. The dot or scalar product of two vectors A and B is defined as:. Find the vectors dot product and the angle between the vectors. The derivative of a vector P according to a scalar variable t is:. The derivative of the product of a vector P and a scalar u t according to t is:. The del operator:. Laplacian operator. Vectors integration.