The document discusses friction, including the forces of static and kinetic friction. It defines friction as the opposing force that resists the motion of one object over another surface. Static friction acts when an object is at rest, and increases up to the limiting friction, at which point the object will start to move and kinetic friction takes over. The laws of friction are discussed, including that friction depends on the surfaces and normal force, acts parallel to the surfaces, and is proportional to the normal force. Both the advantages and disadvantages of friction are summarized.
6-1 FRICTION
After reading this module, you should be able to . . .
6.01 Distinguish between friction in a static situation and a
kinetic situation.
6.03 For objects on horizontal, vertical, or inclined planes in
situations involving friction, draw free-body diagrams and
apply Newton’s second law.
6-2 THE DRAG FORCE AND TERMINAL SPEED
After reading this module, you should be able to . . .
6.04 Apply the relationship between the drag force on an
object moving through air and the speed of the object.
6.02 Determine direction and magnitude of a frictional force.
6.05 Determine the terminal speed of an object falling
through air.
6-3 UNIFORM CIRCULAR MOTION
After reading this module, you should be able to. . .
6.06 Sketch the path taken in uniform circular motion and
explain the velocity, acceleration, and force vectors
(magnitudes and directions) during the motion.
6.07 ldentify that unless there is a radially inward net force
(a centripetal force), an object cannot move in circular motion.
6.08 For a particle in uniform circular motion, apply the relationship between the radius of the path, the particle’s
speed and mass, and the net force acting on the particle. etc...
Friction. Do you know what is friction and how it plays different roles in our general life. There are many section in our life where friction is necessary like - in playing sitar and guitar, walking on the road and to hold something in our hand or in any mechanical devices. But there are many field where friction is not required like - in machines where two surfaces meet at a point. Due to this the life of the machine parts get decreased and failure may be occur there. Know more about different laws of friction, types of friction, elimination of the friction.
Presentation on Friction (Static, Kinetic and Co-efficient of Friction)Md. Sirajul Islam
Friction is an important term, By this presentation I have learned lot about friction, types of friction, major types, application of friction, static and kinetic friction, law of friction, Co efficient of frictions.
I think this all information help you all to understand friction. This information is given by lot of legal sites.
In this lesson, students will learn how gravity & friction can take affect on the simple things we do everyday of our lives. Learn the 3 main types of friction, & air resistance, plus a few examples. Finally, learn about terminal velocity & get a basic introduction to magnetic & electric forces with a slight distinction for buoyancy & density.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
6-1 FRICTION
After reading this module, you should be able to . . .
6.01 Distinguish between friction in a static situation and a
kinetic situation.
6.03 For objects on horizontal, vertical, or inclined planes in
situations involving friction, draw free-body diagrams and
apply Newton’s second law.
6-2 THE DRAG FORCE AND TERMINAL SPEED
After reading this module, you should be able to . . .
6.04 Apply the relationship between the drag force on an
object moving through air and the speed of the object.
6.02 Determine direction and magnitude of a frictional force.
6.05 Determine the terminal speed of an object falling
through air.
6-3 UNIFORM CIRCULAR MOTION
After reading this module, you should be able to. . .
6.06 Sketch the path taken in uniform circular motion and
explain the velocity, acceleration, and force vectors
(magnitudes and directions) during the motion.
6.07 ldentify that unless there is a radially inward net force
(a centripetal force), an object cannot move in circular motion.
6.08 For a particle in uniform circular motion, apply the relationship between the radius of the path, the particle’s
speed and mass, and the net force acting on the particle. etc...
Friction. Do you know what is friction and how it plays different roles in our general life. There are many section in our life where friction is necessary like - in playing sitar and guitar, walking on the road and to hold something in our hand or in any mechanical devices. But there are many field where friction is not required like - in machines where two surfaces meet at a point. Due to this the life of the machine parts get decreased and failure may be occur there. Know more about different laws of friction, types of friction, elimination of the friction.
Presentation on Friction (Static, Kinetic and Co-efficient of Friction)Md. Sirajul Islam
Friction is an important term, By this presentation I have learned lot about friction, types of friction, major types, application of friction, static and kinetic friction, law of friction, Co efficient of frictions.
I think this all information help you all to understand friction. This information is given by lot of legal sites.
In this lesson, students will learn how gravity & friction can take affect on the simple things we do everyday of our lives. Learn the 3 main types of friction, & air resistance, plus a few examples. Finally, learn about terminal velocity & get a basic introduction to magnetic & electric forces with a slight distinction for buoyancy & density.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
1. Force of Friction
Laws of Static and Dynamic Friction
Limits of Friction
Friction – a necessity & evil
FRICTION
2. INTRODUCTION
When an object (e.g., wooden block) moves over the
surface of another object (e.g., floor) , its motion is always
opposed by a retarding force that resists motion.
This retarding force is called friction and always acts in a
direction opposite to motion.
For example, an object sliding down an inclined plane
experiences a frictional force directed up the inclined
plane.
Similarly, an object that moves to the right on a level
floor experiences the frictional force to the left.
3. Friction can operate between two solids, between a
solid and a fluid or between two layers of a fluid.
However, in this chapter, we shall discuss only the
friction between solid surface.
4. FRICTION
When a solid object moves over the surface of
another solid object, its motion is always opposed
by the retarding force, called friction.
Hence friction is an opposing force that comes
into play when one body moves or attempts to
move over the surface of another body. The
frictional force is always parallel to the surfaces in
contact.
Let us discuss how frictional force behaves.
5. Consider a wooden block of mass m placed on a
horizontal surface as shown in Figure 1.
The block pushes down on the horizontal surface
with a force equal to block’s weight (w = mg).
The supporting horizontal surface pushes back with
an equal and opposite force R (= N) so that R = mg.
Fig.1
6. The force R is perpendicular to the surface and is
called normal reaction ( normal means
perpendicular).
Suppose a small horizontal force F is applied on the
block to the right but the block does not move. It
means that a force has come into play to oppose the
motion of the block.
This is the force of friction and is called static
friction because the blocks remains at rest or static
even though we have applied force.
As we increase the applied force, the static friction
also increases till a stage is reached when the block is
about to move.
s
F
s
F
7. The value of static friction is now maximum and is
called limiting friction or critical friction .
Once the limiting friction (i.e., maximum static
friction ) is overcome, the block begins to move and
frictional force decreases. The friction is now called
kinetic friction .
Note that the word kinetic means that the block is
moving. Thus the behaviour of friction can be
summed up as under :
1) Before the body begins to move, the static friction
plays the role ; the static friction increases as the
applied force increases upto the value of limiting
friction (i.e., maximum static friction).
s
F
c
F
k
F
8. 2) Once limiting friction is overcome by the applied
force, the role of static friction is over. Now smaller
frictional force (=kinetic force) opposes the
motion.
3) Both limiting friction ( ) and kinetic friction( )
are important. The limiting friction must be
overcome to start the body moving and then smaller
frictional force to oppose the motion.
k
F
k
F
k
F
c
F
9. TYPES OF FRICTION
There are two common types of friction viz.
1. Static friction 2. Kinetic friction.
1. Static friction :
The opposing force that comes into play when an
object does not move over the surface of another even
though force is applied to make it move is called static
friction.
Consider a wooden block lying on a horizontal surface.
If we apply a small horizontal force (say 1N) on the
block and the block does not move, it means that a
force (=1N) has come into play to oppose the motion.
10. This is the force of friction and is called static friction
As the applied force is increased, the static friction
also increases (being always equal and opposite to the
applied force) till a stage is reached when the block is
about to move.
The value of static friction is now maximum and is
called limiting friction or critical friction .
Note that static friction is always adjusts itself equal
to the applied force upto the value of limiting friction.
Thus limiting friction is the maximum static friction
that comes into play when one body is just at the verge
of moving over the surface of another body.
s
F
c
F
11. Once the limiting friction is overcome by the applied
force, the block begins to move and limiting friction
is converted into kinetic friction .
The subsequent motion of the block is determined by
the applied force (F) and the kinetic friction .
It is reminded that <
Discussion : The following point may be noted :
1. Static friction comes into play only when the
applied force tends to move a body on the surface of
another body. If the applied force is zero, static friction
is also zero.
2. Static friction is a self –adjusting force. As the
applied force increases, static friction also increases
upto limiting friction.
c
F
c
F
k
F
k
F
k
F
12. 2. Kinetic friction :
Kinetic friction is the opposing force that comes into
play when one body moves over the surface of
another body. It is sometimes called dynamic friction.
Once the limiting friction is overcome by the applied
force, the body begins to move and the limiting
friction is converted into kinetic friction.
Fig. 2 shows the graph between the applied force
and force of friction.
The part OA of the graph is a straight line showing
that static friction increases as the applied force
increases upto limiting friction .
c
F
13.
14. The body will remain at rest till the applied force does
not exceed OC. Once the applied force exceed OC, the
body starts moving and friction decreases to (kinetic
friction).
Thus the limiting friction must be overcome to start
the body moving and then a smaller kinetic frictional
force acts on the body to oppose the motion of the
body.
k
F
k
F
15. Types of kinetic friction :
Kinetic friction is of two types viz.
(a) Sliding friction (b) Rolling friction.
When the body slides over the surface of another
body, then opposing force that comes into play is
called the sliding friction.
For example, when a rectangular wooden block is
moved on a level floor, the opposing force is the
sliding friction.
When one body rolls over the surface of another body,
then opposing force that comes into play is called the
rolling friction. Thus when boll rolls over a surface,
the opposing force is the rolling friction.
16. LAWS OF FRICTION
Static friction as well as kinetic friction is a
complicated phenomenon. Many aspects of friction
even today are not completely understood.
However, experiments show that to a good
approximation, the force of friction obeys the
following laws :
1) The frictional force (static as well as kinetic)
depends upon the nature of the two surfaces in
contact and their state of roughness.
2) The frictional force always acts parallel to the
surfaces in contact and its direction is opposite to
motion or attempted motion.
17. 3) The frictional force is independent of the area of
contact of the two surfaces.
4) The magnitude of frictional force (kinetic and
static) is directly proportional to the perpendicular
force (normal reaction R) between the two surfaces
in contact.
5) The frictional force is independent of the speed
(applicable to kinetic friction only) of one surface
relative to the other surface.
18. MAGNITUDE OF LIMITING
FRICTION
Consider a wooden block of
m lying on a horizontal surface
as shown in figure.
The normal reaction R is the
perpendicular force exerted
by the surface on the block.
Clearly, R = mg. If is the limiting friction (i.e.,
maximum static friction), then according to laws of
friction, is directly proportional to the normal
reaction R i.e.,
Applied
force
←Fc
c
F
c
F
19. Fc α R
or Fc = R
Where is a constant of proportionality and is
called coefficient of static friction. Its value depends
upon the nature and condition of the surfaces in
contact.
Therefore, co-efficient of static friction between two
surfaces in contact is equal to the ratio of limiting
friction and the normal reaction.
Since is a ratio of two forces, it has no units i.e.,
it is a pure number.
s
s
c
s
F Limiting friction
R Normal reaction
s
20. ADVANTAGES AND
DISADVANTAGES OF FRICTION
Friction always opposes motion. It has advantages as
well as disadvantages.
Advantages : Although we often view friction as an
undesirable evil and go to great pains to reduce it, we
would really be in deep trouble without it. The following
examples illustrate this point.
1) We would not able to walk if there had been no friction
between the soles of our shoes and the ground. While
walking, we push on the ground and the force of friction
acts in the opposite direction. In the absence of friction,
for example, on icy surface, the person’s shoes would
slip when placed on the ground. The frictional force
always opposes the motion of the shoes.
21. 2) The frictional forces are very beneficial for cars and
other moving vehicles. Without friction between tyres
and the road, the car could not stop, start or turn
corners.
3) The break of car or any moving devices depend upon
friction. When we apply breaks, the car is stopped due
to the force of friction between the break lining and
the drum on the wheel.
4) Friction helps (a) hold screws in wood (b) drive nails
in wood etc.
22. Disadvantages : Friction is associated with many
disadvantages and much of our efforts are directed to
reduce it. The following examples illustrate this point.
1) Much of energy is wasted in overcoming frictional
forces. For example, as much as 20% of the gasoline
burnt in car is used to overcome friction in the
engine.
2) The energy used to overcome the frictional forces is
converted into heat. This raises the temperature. In
almost every machinery, the generation of heat
causes several problems.
3) Since energy due to friction is converted into heat, it
lowers the efficiency of very machinery.