### resistance:

Friction
* All friction source for lost energy.
* Most friction causes charge
  - forces
  - heat
* Most friction creates electricity
  - generates heat
  - produces heat
  - releases energy
* Most friction removes energy
  - mechanical energy
* Related to the normal force is the frictional force.
* Some friction acts on tires
  - applies to materials
  - generates electricity
* Some friction is caused by air
  - attraction
  - water
  - generated by atmospheres
  - occurs in liquids
  - refers to forces
* acts everywhere, and friction produces heat
  - in the opposite way to the direction of travel
* actually helps skis move over the snow.
* also acts in stationary objects
  - causes drag that makes the streams spiral inward toward the central object
* always acts in the direction opposite to movement
  - opposite to air motion and, hence, reduces wind speed
* always acts to oppose any relative motion between surfaces
  - prevent sliding motion between the surfaces at which it acts
  - creates heat
* always opposes motion and makes doing work harder
  - the motion or attempted motion of one surface across another surface
  - reduces the mechanical energy
  - slows down the wind, and therefore also reduces the Coriolis force
* applies mechanical forces to the skin, resulting in increased susceptibility to ulceration.
* becomes factors.
* can also create heat
  - produce motion, as in the case of walking
* can cause grease fires
  - ignition if water content of the material is low
  - come in many forms, but it always resists motion
  - exert an influence on wind only after the air is in motion
  - help keep a slab of snow from sliding downslope
  - rub off the top layer of skin and damage blood vessels under the skin
  - slow or stop moving objects
* causes a skateboard to stop rolling
  - an object to expend additinal energy to attain a certain position
* causes heat which excites the molecular particles of the material
  - in turn excites the molecular particles
* causes the ball to move at a rate proportional to the movement of the mouse
  - decline of speed
* changes the useful work of a machine into mechanical energy.
* comes from hundreds of moving metal parts rubbing against each other.
* common element in daily life
  - form of acceleration
  - topic introduced and investigated during the early age of classical mechanics
* contact force that opposes the relative motion of two surfaces.
* converts energy
  - kinetic energy
  - heat, the enemy of engines far and wide
* decreases productivity in all areas.
* exerts a centripetal force on the car, directed towards the center of the circular track.
* exists everywhere surfaces meet
  - in most of physical manipulators and mechanical control systems
* force between objects that opposes the relative motion of the objects
  - produced by rubbing, that resists motion
  - relating to molecular structure of two surfaces touching each other
* force that acts to slow or stop the motion of objects
  - when two surfaces rub together
* force that can slow an object
  - down moving objects
  - dissipates energy
  - happens when objects rub against one another
* force that holds back the movement of a sliding object
  - one object back against another
  - is created whenever two surfaces move or try to move across each other
* force that occurs between surfaces that are in contact with each other
  - two surfaces where there is motion
  - when one object rubs against another
* force that opposes motion
  - the direction of motion between two materials
* force that opposes the motion of an object or the attempt to move an object
* force that resists movement between two surfaces
  - the sliding or rolling of one solid object over another
* force that slows down moving objects
  - or stops motion between two surfaces that are touching
* generator of sound in solids as well as in gasses.
* happens due to the electro-magnetic forces between two objects
  - when things rub against each other, and it slows down things in motion
* has effects
  - significant effects
* increases energy transfer to the surrounding environment by heating the affected materials
  - the amount of force needed to move an object
  - within seconds after loss of fluid
* involves deep, circular movements of thumbs or fingertips.
* is also responsible for the wear and tear on bike gears and other mechanical parts
  - an important force because it force that affects motion
  - another common cause of skin problems
* is caused by collisions between bumps of varying sizes on two surfaces in contact
  - irregularities in the surface of objects that are touching
* is caused by the irregularities on the two surfaces in contact
  - roughening of the cartilage
  - when two opposing surfaces make contact with each other
  - conflict
  - dependant on the texture of both surfaces
  - dependent on the materials that are in contact with one another
  - divided into two categories, static and kinetic
  - effort
  - given to a healing muscle belly after contusion or in minor muscular tears
  - harmful when it slows our movement by increasing the force needed to move an object
  - higher on rough surfaces than it is on smooth surfaces
  - largest in the atmospheric boundary layer, the air layer nearest the ground
  - less when the surface is smooth
* is one force causes a ball to roll downhill
  - that only exists if air is in motion
* is one of the fundamental forces of nature
  - limiting factors in the design of MEMs devices
  - parts of force that opposes motion
  - opposite of that motion, which is in the direction of the push
* is produced when a match is dragged across a hard surface
  - two materials rub against each other
  - work is done
  - proportional to force per unit area
  - responsible for rolling as opposed to sliding
  - simply the resistant force between two objects moving while in contact with one another
  - sometimes beneficial as when preventing slipping of the feet when walking
* is the cause of most black nails
  - deepest of Swedish massage strokes
  - enemy of speed
* is the force between an object in motion and the surface on which it moves
  - one object rubbing against another object
  - to surfaces rubbing together
* is the force between two objects in contact with one another
  - things that opposes their motion
  - created whenever two surfaces move or try to move over each other
  - exerted by the surface of an object when another object moves against it
  - that allows the car to make it around a turn
* is the force that causes objects rubbing together to slow down
  - to stop moving once they are in motion
  - occurs when two surfaces are in contact with each other
* is the force that opposes motion of one object over another
  - the motion of two objects in contact
* is the force that resists motion between the surfaces of two touching objects
  - the movement of one material over another material
  - results when two objects rub together
  - slows down or stops moving objects
  - stops the bike
* is the main cause of energy loss
  - culprit of wear and tear
  - force acting against the car
* is the major cause of breakdowns in cars and machinery
  - foot ailments like blisters, calluses andhot spots
  - factor in determining how much a ball hooks
  - only thing holding the radius
  - pull and push between an object and the surface across which it is moving
  - reason why the soccer ball always slows down
  - resistance that one surface offers to movement over a second surface
* is the resistance to lateral movement caused by the contact between two surfaces
  - motion of one object moving relative to another
  - relative motion between two bodies in contact
  - sliding of a solid when a contacting body produces the resistance
* is the resisting force of motion between two surfaces when they are in contact
  - to motion
  - retarding force acting against the sliding between two contacting surfaces
  - retrieve force acting between bodies that tends to oppose and damp out motion
  - rubbing of the surface of one object against the surface of another
  - therefore the main cause of energy loss
* is what holds the can in place
  - keeps one foot planted on the ground as the other one steps forward
  - slows down a car or bicycle
  - stops things sliding past each other
  - when an object resists to move over another object
* keeps objects from moving.
* leads to chafing of the skin that, in turn, can result in skin irritation and damage.
* makes everything less efficient, from refrigerators to car engines.
* makes the ice at the bottom of the glacier move more slowly than ice at the top
  - of the glacier move more slowly than the upper portion
  - of the glacier move slower than the upper portion
* measure of the force pressing the two objects together.
* nonconservative force, and there are others
* occurs in almost all situations involving physical objects.
* occurs when one conflicts with the other
  - the bumps and holes of two objects catch and rub together
* occurs when two bodies rub against each other
  - substances rub together
* offers resistance.
* often presents itself as drag, when an object is moving through a fluid medium.
  - the motion of an object and acts to slow it down
* plays a fundamental role in everyday's life
  - an important part in many everyday processes
* produces drag on the wheels to slow or stop the vehicle.
* produces heat and heat involves the microscopic motion of molecules
  - that in some cases can be sufficient to start a fire
  - heat, an essential element of fire
* product of rock texture and force.
* reduces the Coriolis force because it slows down the wind.
* slows down a moving object because it force against motion
  - wind speed and reduces loads
* special kind of force produced by two bodies that are in contact.
* stimulates the genitals and causes the male to ejaculate
  - oils of the skin as it loosens dirt and dead hair
* stress which resists motion and acts in all natural systems.
* surely does, and internal energy losses dominate the repeated collisions between grains.
* surface force that opposes relative motion.
* takes places.
* tends to transfer denser sea water into the overlying fresh water layer.
* then measure of the force pressing the two objects together.
* uses up a portion of the energy as the fluid flows through the lines and components.
* works in a direction opposite to the direction of motion.