i don't understand what magnitude is?

Question

i have just started physics. every now and then, i will see a problem and it asks for the dirrection and magnitude or something and magnitude, or just magnitude. what is magnitude. please make your answer idiot proof please.

thank you!

Answer 1

I know exactly what you're talking about. In the context that concerns you, magnitude is a positive real number that refers to the generalized length of a vector quantity. They're about to introduce vectors, I'm afraid :-( For example, the magnitude of the velocity vector is its speed. If you were walking northeast while climbing a hill, moving north at a rate of 1 mph, east at 1 mph, all the while increasing your altitude a 1 mph, your velocity vector can be written as (1,1,1) mph. The magnitude of this vector is sqrt(3)=1.732, according to the Pythagorean thereom. That's you speed.

Answer 2

Magnitude...
A number assigned to a quantity so that it may be compared with other quantities.

A property that can be described by a real number, such as the volume of a sphere or the length of a vector [See source.]

Whenever you have a problem in definition (like, what does magnitude mean), start with the definitive source...a dictionary. A dictionary is the primary source for definitions; you should use it as such.

When your problem asks for magnitude and direction, it is looking for a vector. Vectors are usually graphed as arrows. The length of the arrow depicts the magnitude of that vector. The orientation of the arrow (which way the pointy end is pointing) is the direction.

Here's a practical example. You are traveling at 160 kph north in your BMW. That's a vector because it has magnitude (160 kph) and direction (north). If you drew this vector, where 1 cm = 1 kph, your arrow would be 160 cm long and the pointy end would point straight up to the top of your paper if that's north.

Answer 3

I'm in physics right now too and magnitude relates to size, extent, and dimensions. It's like the change in distance. Like if a plane is going north-west at 60 degrees at 200 km/s and a wind is going south-east at 40 km/s. The magnitude is how much displacement there is and direction is important in this because how else are you going to know where the shift is? So like try making a triangle knowing this information. The side you don't know is the magnitude. I hope I made some sense, I wish I could have helped more.

Answer 4

Magnitude is the amount. Period. It can be length, time, volume, or weight. It is plain and simple. Amount.

A vector has a magnitude and a direction. A scalar has just a magnitude.

Answer 5

Magnitude may refer to:

Magnitude (mathematics), a measure of the size of a mathematical object:
A vector object has both magnitude and direction as its defining characteristics.
A scalar object has only magnitude as its defining characteristic.
In astronomy:

Hope this helps ~~Sarah~~

Answer 6

Magnitude is simply the 'Size' of something 'How Big'.
Examples.
'I didn't think that the sun had the Magnitude that it is said to have'.
'You shouldn't tell lies of such Magnitude'
'An electron is so small compared to the size of the whole atom, its Magnitude is negligible'.

Answer 7

Longer idiot proof verson:


DIrection is referenced on the "x" axis (direction).
Magnitude is referenced on the "y"axis (direction).


For example:
When we talk of A.C. (alernating current), we are speaking of current that is changing in direction with excursions thru a variety of relatively more negative values to and thru excursions of more positive values. That is to say that the excusions are cyclic.

One excursion of a sine wave is represented below. The sine wave represents 360 degrees of a circle.

The output below is typical of a single phase generator.


(+)
* Maximum Positive Ref
* *
-* -------* ------*------ zero reference line
* *
* Maximum Negative A.C. Ref


In the example below is a representation of a positive D.C. (direct current). It has some amount (Magnitude or amplitude) but no excursions or changes in direction. It is positive and remains so. This is the output is typical of batteries.

-------------------------------positive max D.C. ref
.
_________________ zero reference line



In the example below is a representation of a negative D.C. (direct current). It has some amount (Magnitude or amplitude) but no excursions or changes in direction. It is negative and remains so. This is the output is typical of batteries.

.
_________________ zero reference line


-------------------------------negative max D.C. ref


Shortened Idiot proof version:
Just remember that magnitude is the same as amount and is sometimes called amplitude and is measured in the vertical "y" direction.

I hope this helps.

Unfortunately sine waves did not come out as well as expected.

Answer 8

Magnitude is pretty mush the richtor scale.

Answer 9

Magnitude means, to put it plainly, BIGNESS, AMPLITUDE, or AMOUNT.
For instance, "The magnitude of devastation was tremendous from the earthquake."

Answer 10

Magnitude is a measure of the amount of energy released during an earthquake. It may be expressed using several magnitude scales. One of these, Used in Southern California, is called the Richter scale. To calculate magnitude, the amplitude of waves on a seismogram is measured, correcting for the distance between the recording instrument and the earthquake epicentre. Since magnitude is representative of the earthquake itself, there is thus only one magnitude per earthquake.

Taking the Lawton earthquake of 1998 APR 28, as an example, one could not therefore speak of magnitude 4 at Lawton and magnitude 3 at Tulsa. The effects ( or intensities) at the two places were different, but the magnitude of an earthquake is unique; in this example, it was 4.2 on the Richter scale.

The magnitude scale is logarithmic. This means that, at the same distance, an earthquake of magnitude 6 produces vibrations with amplitudes 10 times greater than those from a magnitude 5 earthquake and 100 times greater than those from a magnitude 4 earthquake.

In terms of energy, an earthquake of magnitude 6 releases about 30 times more energy than an earthquake of magnitude 5 and about 1000 times more energy than an earthquake of magnitude 4.

It is very unlikely that an earthquake of magnitude less than 5 could cause any damage.


Visual magnitude" is a scale used by astronomers to measure the brightness of a star. The term "visual" means the brightness is being measured in the visible part of the spectrum, the part you can see with your eye (usually around 5500 angstroms).
The first known catalogue of stars was made by the Greek Astronomer Hipparchus in about 120 B.C. and contained 1080 stars. It was later edited and increased to 1022 stars by Ptolemy in a famous catalogue known as the "Almagest". Hipparchus listed the stars that could be seen in each constellation, described their positions, and rated their brightness on a scale of 1 to 6, the brightest being 1. This method of describing the brightness of a star survives today. Of course, Hipparchus had no telescope, and so could only see stars as dim as 6th magnitude, but today we can see stars with ground-based telescopes down to about 22nd magnitude.

When astronomers began to accurately measure the brightness of stars using instruments, it was found that each magnitude is about 2.5 times brighter than the next greater magnitude. This means a difference in magnitudes of 5 units (from magnitude 1 to magnitude 6, for example) corresponds to a change in brightness of 100 times. With equipment to make more accurate measurements, astronomers were able to assign stars decimal values, like 2.75, rather than rounding off to magnitude 2 or 3.

There are stars brighter than magnitude 1. The star Vega (alpha Lyrae) has a visual magnitude of 0. There are a few stars brighter than Vega. Their magnitudes will be negative.

Astronomers usually refer to "apparent magnitudes", that is, how bright a star appears to us here at Earth. Apparent magnitudes are often written with a lower case "m" (like 3.24m).

The brightness of a star depends not only on how bright it actually is, but also on how far away it is. For example, a street light appears very bright directly underneath it, but not as bright if it's 1/2 a mile away down the road. Therefore, astronomers developed the "absolute" brightness scale. Absolute magnitude is defined as how bright a star would appear if it were exactly 10 parsecs (about 33 light years) away from Earth. For example, the Sun has an apparent magnitude of -26.7 (because it's very, very close) and an absolute magnitude of +4.8. Absolute magnitudes are often written with a capital (upper case) "M".