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Conditions for constant velocity

We know that the statement means at least the following things:

  • At some point in the past, there was an unbalanced force applied to the object to cause it to begin moving to the right. That force is ignored bythe statement of the problem.
  • At the beginning of the time frame covered by the problem, the object was in equilibrium, moving at a constant velocity to the right.
  • During the time frame of the problem, there must be a 1 newton balancing force being exerted to the left to prevent the 1 newtonforce being applied to the right from causing the object to accelerate towards the right. That force is also ignored by the statement of theproblem.

Use your graph board for sketches

As a sighted person, I often find it useful to make sketches of the physical scenarios for problems of the types that I will discuss in this module.

You may also find it useful to use your graph board to create "sketches" of the physical scenarios in order to better understand the solutions to theproblems.

Work in everyday life

You hear the word work in many situations in everyday life. For example, someone might say "My gasoline bill is high because I have to drive a long wayto work every day."

Someone else might say "She works very hard at being popular."

Or, you might hear someone say "It's going to take a lot of work to lift that heavy sofa into the back of that truck."

The latter expression comes closest to describing what is mean by work in physics.

Work in physics

According to College Physics by Mendenhall et al

If a body on which a force F is acting is displaced by a distance d, then the work done by the force is F*d*cos(theta), where theta is the angle betweenthe path d and the line of action of F.

Thus, the term work has a very precise meaning in physics. In equation form, we can represent work as

W = F * d * cos(theta)


  • W represents work
  • F represents a force that causes the displacement of an object
  • d represents the magnitude of the displacement
  • theta is the angle between the line of action of the force and the direction of the displacement

Three key ingredients

According to the Physics Classroom (see (External Link) ), there are three key ingredients to work: force , displacement , and cause .

In order for a force to qualify as having done work on an object, there must be a displacement and the force must cause the displacement.

Commonplace examples of work

Examples of work are commonplace in everyday life:

  • A bulldozer pushing dirt. The bulldozer exerts a horizontal force to move the dirt.
  • An elevator lifting people from the first to the tenth floor. The cable on the elevator exerts an upward force to move the people upward byapproximately 110 feet.
  • You lifting your backpack full of books onto your back. Your muscles exert a force to raise several heavy books, possibly displacing them bothvertically and horizontally at the same time.

However, some things that we might initially think of as work don't really qualify as work according to the physics definition of work.

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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit 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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