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Natural sciences

Energy transfers and forces

A. forces

Educator section

Memorandum

Fig 1 - A force can change the course (direction) of a moving object.

Fig 2 - A force can halt a moving object.

Fig 3 - A force change the shape of an object.

Fig 4 - A force can change the speed of a moving object.

Fig 5 - A force can make an object rotate.

Leaner section

Content

1. Contact forces

The vehicle in the illustration has broken down and cannot move by itself. The tow truck has to pull it.

This car also cannot move by itself. The man has to push it.

When something has to be pulled or pushed, we say that we must exert force on it. You use the force of thrust to push something away from you, or the force of attraction to pull something towards you.

Examine the following illustrations and indicate whether they show forces of thrust or of attraction.

We cannot see force, but we know that it is there because we observe its effect. The above illustrations show that force can move a stationary object.

Activity: to identify the effect of forces [lo 1.3]

The following illustrations show more of the effect of forces. Are you able to identify them?

Fig. 1: The tennis player hits the ball away from her.

Fig. 2: The driver uses the brakes to stop the car.

Fig. 3 The force of attraction is exerted on the elastic band.

Fig. 4: The force of thrust in the same direction as the motion is exerted on the rolling ball.

Fig. 5: The athlete swings the hammer to rotate it around him

Note down your deductions:

Fig 1: _______________________________________________________________

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Fig 2: _______________________________________________________________

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Fig 3: _______________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

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Fig 4: _______________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

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Fig 5: _______________________________________________________________

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_____________________________________________________________________

_____________________________________________________________________

Sometimes the effect of force is not visible. When you push against a wall, you are using force, but the effect cannot be seen. But when there is an egg between your hand and the wall, you will be able to observe that you have exerted force quite plainly!

2. Forces that operate over distance:

It is even possible to bring objects into motion or to change the direction of the motion without any contact. Forces that affect objects without making contact are identified as forces that operate over distance.

Three kinds of force can have an effect without any contact with objects:

  • Magnetic force
  • Electrostatic force
  • Gravitational force

Assessment

Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

Assessment Standard 1.3: We know this when the learner evaluates data and communicates findings: generalises in terms of relevant aspects and describes how the data support the generalisation.

Questions & Answers

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
Daniel
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
Maciej
characteristics of micro business
Abigail
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
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
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
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
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
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.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natural sciences grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
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