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Joined:	23 Jan 2010
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23 Jan 2010 12:05:58 IST

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Need detailed explanation on sCalar and vector

General

Need detailed explanation on sCalar and vector

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!!**~~AKRITI~~**!!

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Joined: 27 May 2009

Posts: 116

23 Jan 2010 12:55:34 IST

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wich book are u referin 4 physics..?

Krithika B

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Joined: 25 Jan 2010

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25 Jan 2010 22:57:44 IST

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Scalar Quantity:

A physical quantity which is described only by its magnitude. It doesn't have a directon.

A scalar quantity can be represented with a number and a unit.

Scalar quantities of the same unit can be added or subtracted easily, using the normal rules.

Vector Quantity:

A physical quantity which has both magnitude and direction.

When you represent a vector quantity, you have to state the direction (it can also be

"towards object A" or "towards force A", etc.,)

While adding or subtracting vector quantities, you will have to consider the direction.

(Say a force of 20N is acting on an object from east and a force of 10N is acting on the

object from west, then net force=20N + (-10N) towards east= 10N towards east)

Now, i'm pretty confused.. if work is the product of the magnitude of the force acting on

an object and it's displacement (and displacement is a vector quantity), then why is work

a scalar quantity? I better go post a question.

edison

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Joined: 19 Oct 2006

Posts: 7441

9 Sep 2010 14:05:52 IST

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Scalar Quantities:

Scalar quantities requires only one number it has the magnitude ,here we are discussing about the magnitude ,it has no parameter for the directional .There are some examples of the scalar quantities are time ,speed ,,temperature ,volume ,density and the mass .it has only the magnitude not the direction

Example for scalars quantities :

Scalars is defined as the quantity of the magnitude ,there is no direction so it will be declared using the numbers .the speed of the car is 40km/hr it has contains the information of the magnitude only ,their is no direction will be given.

Addition of two scalars:

11 miles + 17miles

scalar addition is just like the ordinary addition ,so the answer is 28 miles .

Subtraction of two scalars:

14 km - 9 km

similarly the scalar subtraction also the same ,so the answer for the above problem is 5 km.

Multiplication of two scalars:

if we are Multiply the following scalars:

11 miles and 9miles

so the multiplication also same for the ordinary one so it is 99 square miles.

Vector Quantities:

A vector is defined as the both the direction and the magnitude ,here in vector the direction field was additionally added it is mainly used for finding the force and displacement of the objects ,displacement is the objects are moving one place to the another place we called as the displacement. Examples of the vectors are the force and the displacement.

Vector Addition:

Here we have to add the following vectors:

Solution:

Now we have to add the above two vectors.

$\displaystyle\text{}{\left({1}{\vec{{x}}}+{7}{\vec{{y}}}+{3}{\vec{{z}}}\right)}+$ $\displaystyle\text{}{\left({6}{\vec{{x}}}+{2}{\vec{{y}}}+{4}{\vec{{z}}}\right)}$

$\displaystyle{\left({1}+{6}\right)}{\vec{{x}}}+{\left({7}+{2}\right)}{\vec{{y}}}+{\left({3}+{4}\right)}{\vec{{z}}}$

$\displaystyle{7}{\vec{{x}}}+{9}{\vec{{y}}}+{7}{\vec{{z}}}$

it is called the resultant vector.

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