Recommendation- Physic Classroom

I LOVE THIS WEBSITE Glenbrook- the Physic Classroom

Scalar and Vector Quantities

Lol, scalar is something without direction like kg, m3 those. while vector is quantity with direction, kgms-1 those (quoted Chikkien)

Yeah, I think I finally got it now, after cikgu Bevina's first, real lesson.

Scalar and Vector Quantities

Figure One

Scalar Quantities

Most of the physical quantities encountered in physics are either scalar or vector quantities.

A scalar quantity is defined as a quantity that has magnitude only.

Typical examples of scalar quantities are time, speed, temperature, and volume.

A scalar quantity or parameter has no directional component, only magnitude.

For example, the units for time (minutes, days, hours, etc.) represent an amount of time only and tell nothing of direction.

Additional examples of scalar quantities are density, mass, and energy.

Vector Quantities (AHA! Vectoring comes from here!)

A vector quantity is defined as a quantity that has both magnitude and direction.

To work with vector quantities, one must know the method for representing these quantities.

Magnitude, or "size" of a vector, is also referred to as the vector's "displacement."

It can be thought of as the scalar portion of the vector and is represented by the length of the vector.

By definition, a vector has both magnitude and direction.

Direction indicates how the vector is oriented relative to some reference axis, as shown in Figure One.

Using north/south and east/west reference axes, vector "A" is oriented in the NE quadrant with a direction of 45 north of the o EW axis.

G iving direction to scalar "A" makes it a vector. The length of "A" is representative of its magnitude or displacement.

In short...

Scalar Quantities: Length, area, distance, work, temperature, time, volume, speed, energy, density

Vector Quantities: Displacement, Velocity, Force, Acceleration, Momentum

Magnitude is defined as... (Wiki)

The magnitude of a mathematical object is its size: a property by which it can be larger or smaller than other objects of the same kind; in technical terms, an ordering of the class of objects to which it belongs. (Huh?)

Direction is defined as... (Wiki)

Direction is the information contained in the relative position of one point with respect to another point without the distance information (Distance is Scalar).

Directions may be either relative to some indicated reference (the violins in a full orchestra are typically seated to the left of the conductor), or absolute according to some previously agreed upon frame of reference (New York City lies due west of Madrid).

I really, really don't understand this. But I shall keep on trying until I do. There are two teachers who are very convicted that girls CAN'T SUCCEED IN PHYSICS and I so wanna prove them WRONG.

Seven Basic Quatities

The international system of units
Or Physics seven (7) Basic quantities

1. Length (meter) -m
   

2. Mass (kilogram) -kg
   

3. Time (second) -s
   

4. Electric current (ampere) -A
   

5. Thermodynamic temperature (kelvin) -K
   

6. Amount of substance (mole) (You shall learn this in chemT/B pg 30) -mol
   

7. Luminous intensity (candela) -cd

Good Physics Website

http://www.physics.org/

Principle of Inertia

Isaac Newton's First Law of Motion states that: Every object continues in its state of rest or of uniform motion unless it is acted upon by an external force.

Which means that, if something is moving, then it will keep on moving until something else stops it (Usually friction against air particles).

Or if something is stationary, then it will not move until something else moves it (Wind, or a itchy foot)

Inertia as defined by Wiki: Inertia is a non-quantifiable property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force.

Or defined by textbook as: Property of the mass of a body which resists change from its state of rest or motion.

The larger the mass of the object, the larger its inertia.

Refer to phyT/B pg31 and 32.