# 2.8 Game 2302-0380 motion -- variable velocity and acceleration  (Page 2/17)

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where

• h is the distance of the projectile above the surface of the earth
• v0 is the initial velocity of the projectile
• t is time in seconds
• g is the acceleration of gravity, approximately 9.8 meters per second squared, or approximately 32.2 feet per second squared at the surface of theearth. (We will also do an exercise involving the acceleration of gravity on the moon.)

(I will provide the other two equations later .)

## Acceleration

Everyone is familiar with the acceleration that occurs when a motor vehicle speeds up or slows down. When the vehicle speeds up very rapidly, the positiveacceleration forces us against the back of the seat. (This involves the relationship among force, mass, and acceleration, which will be the subject of afuture module.)

If the vehicle slows down very rapidly or stops suddenly, the negative acceleration may cause us to crash into the windshield, the dashboard, or adeployed airbag.

The accelerator pedal

A common name for the pedal that causes gasoline to be fed to the engine is often called the accelerator pedal because it causes the vehicle to speed up.(However, I have never heard anyone refer to the pedal that causes the vehicle to slow down as the deceleration pedal. Instead, it is commonly called the brakepedal.)

Definitions

Displacement is a change in position.

Velocity is the rate of change of position or the rate of displacement .

Acceleration is the rate of change of velocity .

Jerk is the rate of change of acceleration (not covered in this module).

According to this author , there is no universally accepted name for the rate of change of jerk .

The algebraic sign of acceleration

When the velocity of a moving object increases, that is viewed as positive acceleration. When the velocity of the object decreases, that is viewed asnegative acceleration.

Uniform or variable acceleration

Acceleration may be uniform or variable. It is uniform only if equal changes in velocity occur in equal intervals of time.

A vector quantity

Acceleration has both direction and magnitude. Therefore, acceleration is a vector quantity.

The units for acceleration

The above definition for acceleration leads to some interesting units for acceleration. For example, consider a situation in whichthe velocity of an object changes by 5 feet/second in a one-second time interval. Writing this as an algebraic expression gives us

(5 feet/second)/second

Multiplying the numerator and the denominator of the fraction by 1/second gives us

5 feet/(second*second)

This is often written as

5 feet/second^2

which is pronounced five feet per second squared.

## The acceleration of gravity

The exercises in the remainder of this module are based on the following two assumptions:

• For practical purposes, the effect of the acceleration of gravity is the same regardless of the height of an object above the surface of the earth,provided that the distance above the surface of the earth is small relative to the radius of the earth.
• In the absence of an atmosphere, all objects fall toward the earth with the same acceleration regardless of their masses.

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
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