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Screen output

When you open the html file in your browser, the text shown in Figure 12 should appear in your browser window.

Figure 12 . Screen output for Listing #2.
Hello from JavaScript vecABv = 0vecABh = 30 vecBCv = 28.284271247461902vecBCh = -28.2842712474619 vecResultMag = 28.336261665087125vecResultAng = 86.5286817554714 The End

Explanation of the code

Listing 2 begins with a copy of the getAngle method that I explained in conjunction with Listing 1 . I won't repeat that explanation here.

Define magnitudes and angles of vectors

Then Listing 2 declares and initializes four variables that represent the magnitude and angle of each of the two vectors. The variable names that end with"mag" contain magnitude values and the variable names that end with "ang" contain angle values, which are converted from degrees to radians.

Compute horizontal and vertical components

Then Listing 2 calls the Math.cos and Math.sin methods to compute the horizontal and vertical components of each vector. The variable names that endwith "h" contain horizontal component values and the variable names that end with "v" contain vertical component values.

Compute the sums of the components

The procedure for adding two or more vectors is to

  • Add the horizontal components of all the vectors to get the horizontal component of the resultant vector.
  • Add the vertical components of all the vectors to get the vertical component of the resultant vector.
  • Compute the magnitude (if needed) of the resultant vector as the square root of the sum of the squares of the horizontal and vertical components.
  • Compute the angle (if needed) of the resultant vector as the arctangent of the ratio of the vertical component and the horizontal component.

Listing 2 computes the sum of the horizontal components from each of the vectors and saves the result in the variable named vecResultH . Then it computes the sum of the vertical components and saves the result in thevariable named vecResultV .

Compute the magnitude of the resultant

In many cases, simply knowing the horizontal and vertical components is the solution to the problem. However, in some cases, it is necessary to convertthose components into a magnitude and an angle.

There are a couple of ways to compute the magnitude. One way is to use the Pythagorean theorem as described above to compute the square root of the sum of the squares of the horizontal and verticalcomponents.

The Math.sqrt and Math.pow methods

The method named Math.sqrt can be called to return the square root of its positive argument. (If the argument is negative, the method returns NaN, whichis an abbreviation for "Not a Number".)

The method named Math.pow can be called to raise the value specified by the first argument to the power specified by the second argument.

Listing 2 calls those two methods to compute the magnitude of the resultant and to save that value in the variable named vecResultMag .

Compute the angle of the resultant

Then Listing 2 calls the getAngle method that we developed earlier to get the angle of the resultant and to save the angle in degrees in the variable named vecResultAng .

Questions & Answers

what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
how to synthesize TiO2 nanoparticles by chemical methods
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Source:  OpenStax, Accessible physics concepts for blind students. OpenStax CNX. Oct 02, 2015 Download for free at https://legacy.cnx.org/content/col11294/1.36
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