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In addition, the script saves the current values of t and h in oldT and oldH to be used to estimate the velocity during the next iteration of the while loop.

Finally, the time value is increased by the value stored in the variable named tInc , and control goes back to the top of the loop where the current value of height is tested to determine if it has become negative(meaning that the arrow has hit the ground).

Acceleration of gravity exercise #1

To repeat the earlier definition, acceleration is the rate of change of velocity.

You learned earlier that velocity is the rate of change of position. Then you learned that we can estimate the velocity of a moving object at a point in timeby determining the slope of a curve that plots the position of the object versus time at that particular point in time.

Positive and negative velocity

Positive slopes indicate positive velocity and negative slopes indicate negative velocity. In the case of ourarrow, the velocity went to zero and switched from positive to negative at the point where the arrow reached its maximum height and began to fall back towardthe earth. In a math class, that point would likely be referred to as an inflection point on the curve of position versus time.

Estimating acceleration

We can extend that procedure to estimate the acceleration of a moving object at a point in time by determining the slope of acurve that plots the velocity of the object versus time at that particular point in time. Positive slopes indicate positive acceleration and negative slopesindicate negative acceleration.

Estimate some velocity values graphically

If you have the velocity curve from Figure 6 plotted on your graph board, I recommend that you estimate and record the slope and hence the acceleration at afew points. That should be easy to do in this case, because the velocity curve should be a straight line with a negative slope.

A constant acceleration value

If the velocity curve is a straight line with a negative slope, and if the acceleration at any point in time is equal to the slope of the velocity curve, thatmeans that the acceleration has a constant negative value throughout the time interval of interest. In fact, you should find that the value of theacceleration is approximately -32.2 feet/second^2, which is known as the acceleration of gravity .

Create a script

Please copy the code from Listing 3 into an html file and open that file in your browser.

Listing 3 . Acceleration of gravity exercise #1.
<!---------------- File JavaScript99.html ---------------------><html><body><script language="JavaScript1.3">document.write("Start Script</br>"); //Declare and initialize constantsvar g = -32.2;//acceleration of gravity in ft/(sec*sec) var v0 = 100;//initial velocity in ft/secvar h0 = 6;//initial height in feet var tInc = 0.25;//calculation interval in seconds//Declare and initialize working variables var t = .0001;//current time in secondsvar h = h0;//current height in feet var v = 0;//current velocity in feet/secvar a = 0;//current acceleration in feet/(sec*sec) var oldT = 0;//previous time in secondsvar delT = 0;//change in time in seconds var oldH = h0;//previous height in feetvar delH = 0;//change in height in feet var oldV = 0;//previous velocity in feet/secvar delV = 0;//change in velocity in feet/sec //The following variable is used to insert spaces in// the output display. var sp = "&nbsp;&nbsp;"; //Compute and display various values for as long as the// height of the projectile is above the ground. while(h>0){ //This is the general equation for the height of a// projectile under the influence of gravity in a // vacuum.h = h0 + v0*t +0.5*g*t*t; //Compute and save the time interval since the// previous estimate of height, etc. delT = t-oldT;oldT = t;//Save the current time for the next iteration. //Estimate the velocity based on the change in// height since the previous estimate. delH = h-oldH;v = delH/delT;//compute velocity oldH = h;//Save the current height for the next iteration.//Estimate the acceleration based on the change in // velocity once the data pipeline is full.delV = v - oldV; oldV = v;//Save the current velocity for the next iteration.if(t>2*tInc){ a = delV/delT;//compute acceleration}//end if //Display the information for this iterationdocument.write( "t = " + t.toFixed(2) + " sec" + sp +" h = " + h.toFixed(0) + " ft" + sp + " v = " + v.toFixed(2) + " ft/sec" + sp +" a = " + a.toFixed(2) + " ft/(sec*sec)" + "</br>"); //Increment the time for the next iteration.t = t + tInc; }//end while loopdocument.write("End Script");</script></body></html>

Questions & Answers

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.
what is biological synthesis of nanoparticles
Sanket Reply
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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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