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# Category Archives: MECHANICS

## DISTANCE

1. Distance covered by a moving object is the total length of the path.
2. It does not depend upon the path followed by the moving object.
3. It does not depend upon the initial and final positions of the moving body.
4. Number of magnitudes of distance between two positions can be infinite. Because there can be infinite number of way to reach from initial to finial position.
5. The nature of path can be curved or straight line.
6. Distance points between two can be equal to or greater than displacement between the same points.
7. The magnitude of distance between two points is always positive.
8. Magnitude of distance can never be zero.
9. Distance is a scalar quantity. Thus it does not require direction.

## VECTOR QUANTITY

There are so many physical quantities, some of them requires only magnitude and some of them requires magnitude as well as direction to express them. Thus a vector is a quantity is a quantity which needs magnitude as well as direction to express it completely. Having only magnitude and direction is not enough to a vector quantity. A vector quantity must follow the laws of vector algebra. For example electric current has both magnitude and direction but it is not a vector quantity. Because electric current does not follow the laws of vector algebra. Now example of vectors are position, displacement, velocity, acceleration, momentum, force, impulse, weight etc. Generally vectors are denoted by bold capital letters with an arrow on their heads. (more…)

## PHYSICAL QUANTITY AND ITS TYPES

A physical quantity is a quantity which can be measured. For example length of a stick, here length is a physical quantity. Similarly volume of water, here volume is a physical quantity. (more…)

## FUNDAMENTAL QUANTITY

1. Fundamental quantities are independent quantities. They do not depend on any other quantities to be expressed.
2. There are total seven fundamental quantities. These are Mass, Length, Time, Electric Current, Temperature, Luminous Intensity and Amount of Substance.

## DERIVED QUANTITY

1. Derived quantities depend on fundamental quantities. Thus a derived quantity is derived from fundamental quantities. For example length and time are fundamental quantities but if we divide length by time then we get speed which is a derivative quantity.
2. There are limitless derived quantities. Examples of derived quantities are as Area, Volume, Force, Pressure, Work, Speed, Velocity, Acceleration, Energy, Power, Torque, Impulse and so on.

## IS CURRENT A VECTOR QUANTITY

No current is not a vector quantity. To be a vector quantity, a physical quantity must have a magnitude, direction and follows the rules of vector algebra. Every current has magnitude. In any circuit electrons flow from negative to positive terminal and hence the current flows from positive to negative terminal. (more…)

## VECTOR QUANTITY

1. A vector quantity depends upon both magnitude and direction of the physical quantity. All vector quantities must follow the law of parallelogram of addition. For example the weight of an object has a magnitude and its direction is always towards the centre of the Earth. Thus weight of an object is a vector quantity. Similarly position of any place is also a vector quantity. Because we canâ€™t describe exact position of any place by only magnitude, we will have to mention the direction too. Example of vectors are displacement, velocity, acceleration, force, impulse etc.
2. Vector quantities follows vector algebra for arithmetic calculations like addition, subtraction, multiplication and division. If two forces of magnitude 3 N and 4 N are acting on a body horizontally and vertically respectively then resultant force on the body will be 5 N.
3. All vectors are represented by bold capital letters with an arrow over them.