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Screen output

The text shown in Figure 5 should appear in your browser window when you open the html file in your browser.

Figure 5 . Screen output for Listing #3.
Start Script Velocity magnitude = 3.00 miles/hourVelocity angle = 0.00 degrees End Script

Analysis of the code

As before, the script begins by defining the getAngle function, which doesn't require further explanation.

The vectorSum function

As you can see from Listing 3 , this script contains a new function named vectorSum . The purpose of this function is to add two vectors, given the magnitude and angle (in degrees) for each vector asincoming parameters. (The function assumes that both incoming magnitude parameters are expressed in the same units.)

The need to add two vectors occurs so often in physics that I decided to encapsulate the capability into a function that we can copy into future scripts.That will relieve us of the need to rewrite the code each time we need that functionality.

Return an array object

The magnitude and the angle (in degrees) of the resultant vector is returned in a two-element array object, with the magnitude in the element at index 0 and the angle in the element at index 1.I will have a more to say about arrays shortly.

Note that this function calls the getAngle function, which must also be provided in the script.

Subtraction of vectors

The function can also be used to subtract one vector from another. To subtract one vector from another, simply add 180 degrees to the angle for the subtrahend vector before passing the angle to the function.

Adding more than two vectors

Although the function can only be used to add two vectors, it can be called repeatedly to add any number of vectors two at a time.

To use this function to add more than two vectors, add the first two vectors as normal. Then add the vector output from the function to the third vector, etc., until all of the vectors have been included in the sum.

The code in the vectorSum function

Most of the code in the function is the same as code that I have explained in earlier modules. However, there are a couple of lines of code that aredifferent.

The function begins with the following statement:

var vecResult = new Array(2);

The purpose of this statement is to create a two-element array object named vecResult .

What is an array object?

You can think of an array object as a software object containing pigeon holes into which you can store data and from which you can later retrieve that data. This particular arrayobject has two pigeon holes, and they are numbered 0 and 1.

This array object will be used as a container to return the magnitude and angle values for the resultant vector.

Can only return one item

A JavaScript function can only return one item. Up to this point in these modules, that item has consisted of a single numeric value, such as the anglevalue that is returned from the getAngle function.

However, the vectorSum function needs to return two different values. One way to do that is to put those two values in the pigeon holes of an array object andreturn that array object as the one item that can be returned.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
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
there is no specific books for beginners but there is book called principle of nanotechnology
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?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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