# 3.1 Forces and friction

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## [lo 1.1; lo 1.3; lo 3.1]

Write a report (three A4 sheets) on Isaac Newton and on his contribution to science. Also refer to the saying 'The apple never falls far from the tree'. Include your report in the module as extra pages following this one.

Assessment of RESEARCH

Were you able to find out who Isaac Newton was and do you understand his contribution to science?

[LO 1.1; LO 1.3; LO 3.1]

## [lo 2.3; lo 2.4]

The earth attracts all objects that are in its proximity.

• We know the following:
• all objects have mass and all masses exert tractive force (pull); this mostly is not observable;
• the greater the masses, the greater the tractive force; as the earth is large, we only observe tractive force in one direction (i.e. as the earth attracting our bodies);
• the closer the proximity between masses, the greater the tractive force between them.
• The mass of an object serves as an indication of the amount of matter and this is measured in
• The weight of an object signifies the amount of tractive force (pull) that the earth exerts on the particular object.
• The tractive force which attracts objects to the earth is known as gravitation .
• The unit for measuring force is NEWTON (N).

The weight of an object that has a mass of 100 g is 1 N

• This is roughly equal to the weight of a small banana or a small apple.

Questions:

1. ONE kilogram has a weight of .........................N.

2. Your mass will remain the same, no matter where you may be in the universe, but your weight will vary. Explain this. ( Refer to the module dealing with space programmes.)

3. What is your mass?..................................................

4. What is your weight?..................................................

5. What would your weight be on the moon where the tractive force is 0,6 N?

6. FORCE and WEIGHT are both measured in NEWTON. Explain this.

7. You are able to observe the effect exerted on an object by the force of attraction if you lift it up by means of an elastic band. This demonstrates the principle behind the SPRING BALANCE.

8. Describe the difference between a spring balance and a bathroom scale.

[LO 2.1; LO 2.3; LO 2.4]

## [lo 1.2; lo 2.4]

Measure the weight of a number of objects with the help of a calibrated spring balance.

• First measure the weight after suspending the object from the spring balance by means of a length of string.
• Then place the object on the floor and pull it along to get a reading. Note down both readings.
• Repeat each operation three times for each object.

Assessment of the ability to measure weight/force by means of a spring balance

[LO 1.2]

QUESTIONS

1. What is inside the spring balance to make it possible to take a measurement?

2. Why do the two readings differ?

3. What is the meaning of calibrated ?

4. What would the weight of a 2,5-kg bag of sugar be?

5. What is the purpose of the adjustment for zero on the spring balance?

6. Identify the forces that are present.

7. Distinguish between weight and mass.

#### Questions & Answers

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
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
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
characteristics of micro business
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
Berger describes sociologists as concerned with
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