# 0.11 Phy1080: motion -- variable velocity and acceleration  (Page 10/19)

 Page 10 / 19

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>```

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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