Friction is a force that opposes the relative motion between two surfaces in contact. The amount of friction depends on the type of surfaces and the force pressing them together. Friction can be beneficial by allowing us to grip objects, but also harmful as it causes wear and reduces efficiency. Rough surfaces have more friction than smooth surfaces due to more contact points. Friction converts kinetic energy into thermal energy, and lubricants can reduce friction to improve machine efficiency.
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.
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.
Friction is a force that slows down moving objects or prevents stationary objects from moving .
Friction is a contact force .
Friction produces heat .
For example – A matchstick
Friction opposes the motion of an object
When one surface moves over another , these grooves and ridges get caught up with each other and slow down the motion . This causes friction .
Friction is known as the resistance to motion of one object moving relative to another. According to scientists it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
the relation between force and motion id described in Newtons three laws of motion. These laws are very simple statements and enable us to describe the future (or past) motion of body if we know the forces acting on it.
Friction is a force that slows down moving objects or prevents stationary objects from moving .
Friction is a contact force .
Friction produces heat .
For example – A matchstick
Friction opposes the motion of an object
When one surface moves over another , these grooves and ridges get caught up with each other and slow down the motion . This causes friction .
Friction is known as the resistance to motion of one object moving relative to another. According to scientists it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
the relation between force and motion id described in Newtons three laws of motion. These laws are very simple statements and enable us to describe the future (or past) motion of body if we know the forces acting on it.
Kinds of Friction
A moving object is affected by friction. However, the amount of friction may vary depending on the type of surface the object gets in contact with.
Rolling Friction
When an object rolls over a surface , rolling friction is produced. One of the most common examples of rolling friction is the movement of motor vehicle tires on the road , a process that generates heat and sound as by-products. Rolling friction is easier to overcome than sliding friction for similar materials. This type of friction is important to engineers who design certain products. For example, skates, skateboards, and bicycles need wheels that move freely.
Sliding Friction
Sliding friction occurs when two solid surfaces slide over each other. Sliding friction can be useful. For example, you can spread sand on an icy path to improve your footing. Ballet dancers apply a sticky powder to the soles of their ballet slippers so they won’t slip on the dance floor. And when you stop a bicycle with hand brakes, rubber pads slide against the tire surfaces, causing the wheels to slow and eventually stop. On the other hand, sliding friction is a problem if you fall off your bike and skin your knee!
Fluid Friction
Fluids, such as water, oil, or air, are materials that flow easily. Fluid friction occurs when a solid object moves through a fluid. Like rolling friction, fluid friction is easier to overcome than sliding friction.
Static Friction
The friction that acts on objects that are not moving is called static friction. Because of static friction, you must use extra force to start the motion of stationary objects. For example, think about what happens when you try to push a heavy desk across a floor. If you push on the desk with a force less than the force of static friction between the desk and the floor, the desk will not move. To make the desk move, you must exert a force greater than the force of static friction.
Best ppt on friction explaination, types of friction ,advantage & disadvantage of friction.effects of friction, methods of increacing and reducing friction,with example
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
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Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
4. Friction is a force that opposes motion between
two surfaces that touch each other.
1
5. You will find friction everywhere that objects
come into contact with each other.
The force acts in the opposite direction to the
way an object wants to move.
2
6. 1. The type of surfaces in contact.
2. The amount of force pressing the surfaces
together.
The amount of friction between two surfaces
depends on:
3
7. What Creates More Friction?
• Rough Surfaces
– Rough surfaces have more microscopic hills & valleys.
– The rougher the surface, the greater the friction will be.
• Greater Force
– The amount of force exerted increases the amount of
friction
– Changing the amounts of the surfaces that touch does
NOT change the amount of friction.
4
9. To the naked eye a material may seem smooth, such
as the polished mica pane shown below.
10. At the microscopic level, even the smoothest surfaces
are covered with dips and bumps.
Picture of extremely smooth mica with a scan probed
microscope.
If you look at it at mica at the microscopic level, it will
appear rough.
11. The tips of the bumps are the only points that touch the
other material. Only a very small portion of the apparent
surface area is in contact with the other surface.
This causes extremely high pressure to form on the parts
that touch. The microscope ridges between two surfaces
can get stuck in the grooves of the other, effectively
creating a type of mechanical bond, or microweld, between
the surfaces.
6
18. There are two kinds of friction: static friction
and kinetic friction:
Static friction is the force between two stationary objects.
static friction is always greater than kinetic friction.
Static friction prevents an object from moving against a
surface. It is the force that keeps a book from sliding
off a desk, even when the desk is slightly tilted, and that
allows you to pick up an object without the object slipping
through your fingers.
In order to move something, you must first overcome the
force of static friction between the object and the
surface on which it is resting.
9, 10, 11
19. Once two objects are in motion it is easier to
keep them in motion.
When two surfaces are in motion with respect to
each other there is Kinetic friction.
There are several types
of kinetic friction,
including sliding friction
and rolling friction.
12,13
20. Sliding friction resists the motion of an object as it moves
along a surface.
Sliding friction, is created by flat objects moving
against each other.
14
23. Rolling friction hinders the motion of an object
rolling along a surface.
Another force must be present to keep an object
rolling. For example, a pedaling bicyclist provides
the force necessary to the keep a bike in motion.
When one surface is rolling over another surface
there is rolling friction.
16,17
25. When the Great Pyramids were being build in ancient
Egypt, they used logs as rollers under the giant blocks of
granite instead of trying to slide the rocks along the
ground.
26. Friction Can Be Harmful or Helpful
• Harmful friction
– Holes in socks or knees of jeans
– Wind & water cause erosion
• Helpful friction
– Friction between pencil & paper
– Without friction, you would just slip &
fall when you tried to walk
19,20
27. Rotors and brake shoes on a Porsche.
Brake pads in your car help produce friction to slow you down
28. We have contours in our skin's surface called friction ridges
that help the hand to grasp by increasing friction. Friction
ridges occur in patterns (fingerprint).
29.
30. The skateboard has a layer of grip tape on its surface for
the sole purpose of creating friction between the
skateboarder's shoe and the skateboard.
31. This is what keeps the board under the skateboarder's feet
as he jumps into the air. This friction allows skateboarders to
flip the board, jump with the board, and stay on the board at
all times.
32. In much the same way, skateboarders turn in midair by
twisting their arms and legs in opposite directions. Upon
landing, a skater can use the friction between his or her
feet and the skateboard to twist the upper body back
into alignment.
34. A cracked and worn disc brake pad
In machines with moving parts, friction increases wear,
produces heat and reduces efficiency.
21
35. While friction allows us to
convert one form of motion to
another, it also converts some
energy into heat, noise, and
wear and tear on material.
Losing energy to these effects
often reduces the efficiency of
a machine.
In automobiles and airplanes, friction converts some of the
energy in the fuel into heat, noise, and wear and tear on
the engine’s parts.
Excess frictional heat can damage an engine and braking
system.
22
36. Averaged over urban and highway
conditions, the average mechanical
efficiency is around 52% for typical
automobiles.
Much of the energy is lost in overcoming
friction in operating the engine.
The types of friction include energy
necessary for pumping (moving the
intake and exhaust valves), energy to
overcome rubbing friction, and energy
required to operate accessories such as
the air conditioner.
http://www.parcon.uci.edu/paper/Conservation/energy.htm
23
39. Friction Reduction
• Ways to reduce friction
– Lubricants- Substances applied to
surfaces to reduce the friction between
them
– Switching from sliding friction to
rolling friction by the use of ball
bearings
– Make surfaces that rub together
smoother
25
40. Remember:
Friction is a force that opposes motion.
Standard friction equation
Friction = coefficient of friction x normal force.
41. Measures of friction are based on the type of materials that
are in contact.
Each material has what is known as a coefficient of
friction. The coefficient is a measure of how easily one
object moves in relationship to another.
When you have a high coefficient of friction, you have a lot
of friction between the materials.
Concrete on concrete has a very high coefficient of
friction.
A material such as Teflon (on most things) has a very low
coefficient. Teflon is used on surfaces where we don't want
things to stick; such as pots and pans.
How is friction measured?
26,27,28
42. = coefficient of kinetic friction
= coefficient of static friction
FN = the normal force
μk
μs
29,30,31,32,33,24
μ = Symbol for the Greek letter mu, used in
the formula to represent the coefficient.
43. The coefficient of kinetic friction between a block and
the level surface it slides on is 0.45.
If the mass of the block is 10.0 kg, what is the
minimum force needed to keep the block moving with
uniform motion?
The applied force need only balance the kinetic
frictional force in order to maintain uniform motion.
Fk = µ kFN
Fk = µ kFN
Fk = (0.45)(10.0)(9.8
m/s2
Fk = 44 N
44. A student pulls a 5.00 kg object and discovers that she
needs to exert 30.0 N of force before the object moves.
What is the coefficient of static friction between the
object and the surface on which it rests?
Since the applied force is
Equal to 30 N just before
Moving, the friction force
Must be equal in size (30 N).
Therefore:
45. A 7.30 kg box is at rest on a level table. The coefficient
Of static friction between the box and table is 1.03.
How big is the static frictional force?
There is no static frictional
force acting since there is no net
force attempting to move the
box.
The static frictional force could,
at most be equal to μstaticFN