U.S. TRADEMARK APPLICATION NO. 77418246 — SPD—00O2
`
`Page 1 of5
`
`T0:
`
`Sutro Product Development, Inc. (trademarks@c)gpher1aw.cgm)
`
`Subject:
`
`U.S. TRADEMARK APPLICATION NO. 77418246 — SPD-0002
`
`Sent:
`
`9/10/2010 3:43:25 PM
`
`Sent As:
`
`ECOM104@USPTO.GOV
`
`Attachments: Attachment - 1
`
`Attachment - 2
`
`Attachment - 3
`
`Attachment -4
`Attachment - 5
`
`Attachment - 6
`
`Attachment — 7
`Attachment - 8
`
`Attachment - 9
`
`Attachment - 10
`
`Attachment -_],1
`Attachment - 12
`
`Attachment - 13
`
`Attachment -0104
`Attachment - 15
`Attachment - 16
`
`UNITED STATES PATENT AND TRADEMARK OFFICE (USPTO)
`OFFICE ACTION (OFFICIAL LETTER) ABOUT Al'PLlCAN'l“S TRADEMARK APl’LlCA'l‘l0N
`
`APPLICATION SERIAL NO.
`
`77418246
`
`CLICK IEERE T0 RESPOND TO TIIIS LETTER:
`http://www.uspt0.gov/teas/eTEASpageD.htm
`
`CORRESPONDENT ADDRESS:
`
`Charles R. Cypher
`LAW OFFICES OF JAMES R. CYPHER
`409 13th Street, 11th Floor
`Oakland CA 94612
`
`APPLICANT:
`Inc.
`
`Sutro Product Development,
`
`CORRESPONDENT’ S
`REFERENCE/DOCKET NO:
`SPD-0002
`CORRESPONDENT E-MAIL ADDRESS:
`
`trademarks@cypherlaw.com
`
`OFFICE ACTION
`
`STRICT DEADLINE TO RESPOND TO THIS LETTER
`
`file://\\ticrs-ais-01\ticrsexpo1t\Htm1ToTif‘IInput\OOA0001201O_09_13#09_56A36_WS194...
`
`9/13/2010
`
`

`
`U.S. TRADEMARK APPLICATION NO. 77418246 — SPD—0OO2
`
`Page 2 of 5
`
`TO AVOID ABANDONIVIENT OF APPLICANT’S TRADEMARK APPLICATION, THE USPTO MUST
`RECEIVE APPLICANT’S COMPLETE RESPONSE TO TPHS LETTER WITHIN 6 MONTHS OF THE
`ISSUE/1\/IAILING DATE BELOW.
`
`ISSUE/MAILING DATE: 9/10/2010
`
`THIS IS A FINAL ACTION.
`
`TEAS PLUS APPLICANTS MUST SUBMIT DOCUMENTS ELECTRONICALLY OR SUBMIT
`
`FEE: Applicants who filed their application online using the reduced-fee TEAS Plus application must
`continue to submit certain documents online using TEAS, including responses to Office actions. See 37
`C.F.R. §2.23(a)(1). For a complete list of these documents, see TMEP §819.02(b).
`In addition, such
`applicants must accept correspondence from the Office via e-mail throughout the examination process
`and must maintain a Valid e-mail address. 37 C.F.R. §2.23(a)(2); TMEP §§8l9, 819.02(a). TEAS Plus
`applicants who do not meet these requirements must submit an additional fee of $50 per international
`class of goods. 37 C.F.R. §2.6(a)(1)(iV)', TMEP §819.04.
`In appropriate situations and where all issues
`can be resolved by amendment, responding by telephone to authorize an examin-er’s amendment will not
`incur this additional fee.
`
`This action is in response to applicant’s letter, dated August 17th, 2010, in which applicant 1) submitted
`arguments against a functionality refusal, 2) submitted arguments against a failure to function refusal,
`and 3) requested amendment of the application to the Supplemental Register in the alternative. Since
`the applicant’s arguments were unpersuasive as to the failure to function refusal, the application has
`been amended to seek registration on the Supplemental Register, and as a result, the failure to function
`refusal under Sections 1, 2, and 45 of the Trademark Act are withdrawn. But as discussed below, the
`functionality refusal is continued and made FINAL.
`
`FUNCTIONAL MARK — FINAL REFUSAL
`
`Registration is refused because the applied-for mark, which consists of a sound, appears to be functional
`for such goods. Trademark Act Section 2(e)(5), 15 U.S.C. §l052(e)(5)', see TMEP §1202.02(a)—(a)(ii).
`A feature is functional if it is “essential to the use or purpose of the [product]” or “it affects the cost or
`quality of the [product]." TrafFix Devices, Inc. v. Mktg. Displays, Inc., 532 U.S. 23, 33, 58 USPQ2d
`1001, 1006 (2001); Qualitex Co. v. Jacobson Prods. Co., 514 U.S. 159, 165, 34 USPQ2d 1161, 1163-64
`(1995); TMEP §l202.02(a)(iii)(A). The refusal is continued and made FINAL.
`
`Applicant’s mark is the sound of a small metal object striking another metal object. The metal objects
`are struck in order to provide resistance to the hinges so that the temples “lock” into the open or closed
`position. The sound is functional because eliminating the sound would increase the cost of producing
`the product.
`
`A determination of functionality is a question of fact, and depends on the totality ofthe evidence
`presented in each particular case. Valu Eng ’g, Inc. v. Rexnord Corp, 278 F.3d 1268, 1273, 61 USPQ2d
`1422, 1424 (Fed. Cir. 2002); In re Caterpillar Inc., 43 USPQ2d 1335, 1339 (TTAB 1997); TMEP
`§l202.02(a)(iv). Additionally, a determination that an applied—f0r configuration mark is functional
`constitutes an absolute bar to registration on the Principal or Supplemental Registers, regardless of any
`evidence of acquired distinctiveness. Trademark Act Sections 2(e)(5) and 23(0), 15 USC. §§l052(e)
`(5), 1091(c); see TrafFix Devices, Inc. v. Mktg. Displays, Inc., 532 US. 23, 29, 58 USPQ2d 1001, 1.006
`(2001); In re Controls Corp. of/lm., 46 USPQ2d 1308, 1311 (TTAB 1998); TMEP §1202.02(a)(iii)(A).
`
`Applicant argues, “the three click hinge adds nothing functional to the sunglasses . .. The three click
`
`file://\\ticrs—ais-O1\ticrsexport\HtmlToTiffInput\OOAOOO12010_09_l3_09_56_36_WSl94...
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`9/13/2010
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`

`
`U.S. TRADEMARK APPLICATION NO. 77418246 - SPD-0002
`
`Page 3 of5
`
`hinge is not essential or even advantageous to the function of Applicant's goods.”
`
`Applicant’s most recent Office action response, however, states the following:
`
`Applicant has also previously provided the Examiner with two United States Patents that describe
`and show how cam surfaces in conjunction with a spring biased cam follower provide resistance to
`movement of the temples. Neither of these references refer to any sounds made by the cam
`surfaces, thereby further demonstrating that the sounds are merely an incidental effect of the
`operation of the hinges not a necessary part of their operation for providing resistance to
`movement. The sound exists as a result of operation of the hinge...
`
`(Boldness added.)
`
`Applicant therefore admits that the manner in which the hinges operate are covered by two United States
`Patents. Utility patents claiming the features at issue are strong evidence of functionality. TrafFix
`Devices, Inc. v. Mktg. Displays, Inc, 532 U.S. 23, 29-30, 58 USPQ2d 1001, 1005 (2001); see TMEP
`§1202.02(a)(iv), (a)(v)(A).
`
`And although applicant is correct in its assertion that the patents do not mention sound in any way, the
`applicant does admit that the sounds are emitted as a result of the operation of the hinge. Therefore,
`the resulting sound is a natural result of the friction created by the patented feature, and is thus also
`functional.
`
`Specifically, the term “FRICTION” means “surface resistance to relative motion, as of a body sliding or
`rolling; the rubbing of the surface of one body against that of another.” See attached dictionary
`evidence. One of the major byproducts of friction is sound. See attached evidence from Cornell
`University.
`
`Because applicant’s goods involve a racheting hinge mechanism that involves metallic and/or plastic
`components rubbing against each other to provide resistance, the sound produced is a natural byproduct
`of the friction created by the patented hinge mechanism.
`
`In order to reduce or eliminate the sound, applicant would have to develop a system to greatly reduce the
`friction created when operating the hinge mechanism, which could be achieved through the addition of
`lubricants or bearings. See attached evidence discussing ways to reduce friction. Because adding
`lubricants or bearings to greatly reduce the friction would increase the cost of manufacturing the
`product, the current sound emanating as a result of the operation of the hinges is a functional feature of
`the goods.
`
`And with respect to the functionality of the hinge mechanism itself, applicant’s own advertising is also
`strong evidence that the matter sought to be registered is functional when it extols specific utilitarian
`advantages of the applied-for product. TMEP §l202.02(a)(v)(B); see, e.g., In re Gibson Guitar Corp.,
`61 USPQ2d 1948 (TTAB 2001); M-5 SleelMfg., Inc. v. 0 ’Hagz'n ’s Inc., 61 USPQ2d 1086 (TTAB
`2001).
`
`Applicant’s advertising states that the three click hinge is functional and serves and advantage over other
`sunglasses. For example, applicant’s advertising states “[w]e’ve introduced the Ratchet Hinge T“, a
`combination of form and function that is unmatched in strength, durability and fit,” and that the hinge is
`“integrated into the frame for incredible strength and durability,” and that it “allows the use of a lighter.
`more comfortable spring, keeping the frame centered on the face without oppressive pressure.”
`
`file://\\ticrs-ais-O1\ticrsexpoit\HtmlToTiffInput\OOA000120l0_O9_13_09_56_36_WS194...
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`9/13/2010
`
`

`
`U.S. TRADEMARK APPLICATION NO. 77418246 - SPD-0002
`
`Page 4 of5
`
`Furthermore, applicant’s own submitted advertising states “the new Three Click Hinge used in this
`collection addresses the weakest point in conventional eyewear construction. The hinge uses a
`revolutionary 3-D lance design that anchors the hinge into the frame from all directions,” and goes on to
`state that the “Three Click Hinge” is “l0X stronger than a conventional hinge.”
`
`Because the sound is naturally emitted as a result of the friction created by operating the rachcting hinge,
`and eliminating this sound through lubricants or bearings would increase the cost to manufacture the
`product, the sound is refused for being functional under Section 2(e)(5) of the Trademark Act. The
`refusal is continued and made FINAL.
`
`RESPONDING TO A FINAL ACTION
`
`If applicant does not respond within six months ofthe date ofissuance of this final Office action, the
`application will be abandoned. 15 U.S.C. §l062(b)', 37 C.F.R. §2.65(a). Applicant may respond to this
`final Office action by:
`
`(1) Submitting a response that fully satisfies all outstanding requirements, if feasible; and/or
`
`(2) Filing an appeal to the Trademark Trial and Appeal Board, with an appeal fee of $100 per
`class.
`
`37 C.F.R. §§2.6(a)(18), 2.64(a); TBMP ch. 1200; TMEP §714.04.
`
`In certain rare circumstances, a petition to the Director may be filed pursuant to 37 C.F.R. §2.63(b)(2) to
`review a final Office action that is limited to procedural issues. 37 C.F.R. §2.64(a); TMEP §7l4.04; see
`37 C.F.R. §2.146(b); TBMP §l201.05; TMEP §l704 (explaining petitionable matters). The petition fee
`is $100. 37 C.F.R. §2.6(a)(l5).
`
`If applicant has questions about the application or this Office action, please telephone the assigned
`trademark examining attorney at the telephone number below.
`
`/Jason Paul Blair/
`
`Examining Attorney
`Law Office 104
`
`Phone - (571)272-8856
`Fax - (571)273-8856
`
`TO RESPOND TO THIS LETTER: Use the Trademark Electronic Application System (TEAS)
`response form at http://teasroauspto.gov/roa/. Please wait 48-72 hours from the issue/mailing date
`before using TEAS, to allow for necessary system updates of the application. For technical assistance
`with online forms, e-mail TEAS(a2uspto.gov.
`
`It must be personally signed by an individual applicant
`WHO MUST SIGN TIIE RESPONSE:
`or someone with legal authority to bind an applicant (i.e., a corporate officer, a general partner, all joint
`applicants). If an applicant is represented by an attorney, the attorney must sign the response.
`
`PERIODICALLY CHECK THE STATUS OF THE APPLICATION: To ensure that applicant
`does not miss crucial deadlines or official notices, check the status of the application every three to four
`months using Trademark Applications and Registrations Retrieval (TARR) at lntp://tarr.uspto.gov/.
`
`file ://\\ticrs-ais-O1\ticrsexpoit\HtmlToTifTInput\OOA000l 20 l 0_O9_1 3_09_5 6_36_WS l 94...
`
`9/13/2010
`
`

`
`U.S. TRADEMARK APPLICATION NO. 77418246 - SPD-0002
`
`Page 5 of 5
`
`Please keep a copy of the complete TARR screen. If TARR shows no change for more than six
`months, call 1-800-786-9199. For more information on checking status, see
`http://www.uspto.gov/trademarks/process/status/ .
`
`TO UPDATE CORRESPONDENCE/E—MAIL ADDRESS: Use the TEAS form at
`http://www.uspto.gov/teas/eTEASpageE.ht.rn.
`
`file://\\ticrs-ais-O1\ticrsexport\Htm1T0TifT'Input\OOA00012010_09_13_09_56_36_WS194...
`
`9/13/2010
`
`
`
`

`
`htt zlfwwwtheweather rediction.com/hahyhin1sf2E!3/
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`HOW DOES WIND CREATE SOUND?
`NIETEOROLOGIST JEFF HABY
`
`W; E
`
`On awindy day, a hodgepodge of sounds can be heard outside. Some ofthe sound is like whistling E
`sound, some sound is like small objects falling I rolling and some sound is like objects rubbing into
`each other. There are three main contributions to the sound. Each of these is discussed below:
`
`i
`
`1. Friction- Friction occurs when objects rub over each other. When the air speed increases, the
`
`friction over objects increases also. The process of fxicliuu can release sound especially as wind
`speed becomes very high. The friction between air and objects can produce Whistling sounds and
`swooshing sounds.
`
`2. Falling I rolling objects- At higher Wind speeds objects are more inclined to fall off oftrees and
`buildings. These objects falling to the ground and rolling along the groundwill create sound.
`
`3. Ohinnt rnhhimI- VVhP.n the wind increases. nhiects hit un aaainst each ntlmr mnre. This is
`
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`httpzl/wvwv.theweatherprediction.comfhabyhints/28$
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`U9/1Df2U1D 03:35:48 PM
`
`§ 3. Ubject ruhbing- When the wind increases, objects hit up against each other more. This is
`E especially true for vegetation. Higher wind blows txees stems and leaves around more causing
`them to bump into each other and to create sound.
`
`On awindy day, close your eyes and listen to all the sound. Try to pick out in your mind what is
`: creating each individual sound.
`
` L Trick of a tinx helix :
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`'cut'doJm' u 6;: o? your'ben'y'eJery
`day by using this 1 weird old up.
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`hI t
`09/10/2010 03:39:21 PM
`://dictionar .reference.com/browse/friction
`
`Dictionary
`
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`
`Encyclopedia
`
`Translator
`
`Search
`
`%ctionary.com
`
`friction
`
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`friction ~
`
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`
`-.‘ii«:‘~iii"»n:'ii‘j;is-zizltr
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` ofil/our components Reduce
`Friction, Temperature 8: Wear
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`fric-tion :1)’; [frik-shah n] 62’ Show IPA
`
`—noun
`of 3 tioiii; slicliiiri or
`;‘~.i,iiiTai:e ieai~iIaii~;+:« to i»;-|3'_i'«.-'e m«:«ti:-i'i. as
`ri:i|lii’ii i_.
`flu: ii,iLiLiiiir'i oi
`
`.1l|l:.lH7il.:’i‘.
`dissension or conflict between persons, nations, etc:.,
`because of differing ideas, wishes, etc.
`
`l,l‘iv:
`
`‘;“l.ii’l-Jlik? of iiiriif:
`
`l=i§iCi'-,«' —3::i.Jii’i:..t
`
`
`
`i’i‘i.al. or
`
`
`
`
`3.
`
`Origin:
`1575-BS; < L fri'cti'on— (s. of friend ) a rubbing, equiv. to frict
`(us ) (ptp. of fricere ) + —.f6n-
`-ion
`
`——Related forms
`fric - tion—less. aciiective
`
`Related Searches
`
`Different types of fr...
`Sliding friction
`Friction experiments
`Forces and friction i...
`
`Rolling friction
`Friction studies
`Static friction
`Friction force
`Coefficient of fricti...
`
`Explaining friction
`Fluid friction
`Friction useful
`
`Synonyms
`intei'ferei'ice
`irritation
`resistance
`
`antagonism
`discontent
`dissension
`
`opposition
`
`More Synonyms 1»
`
`Nearby Words
`
`frick, henry clay
`frickle
`fries
`,.,.
`
`

`
`http:/ldictionary.reference.com/browse/‘friction
`
`09/10/2010 03:39:21 PM
`
`friction
`
`friction clutch
`friction i:lutche<3
`Friction cost
`iv
`
`mc-tion-iess, adjective
`fric-tion-less~|i,r, adverb
`in-ter~fric-tion, noun
`non>fric-tion, noun
`self—fricticin, noun
`
`~53/nonyms
`3. discord, dissidence, clash, antagonism, contention, wrangling.
`
`Related Questions
`What is the def-lnmon of
`fnwon
`how to reduce friction
`
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`"M Related ‘NOI'dS fi’.‘iI‘ I friction
`clash, rubbing, detrition
`.
`View more related words >>
`
`FasterS non ms
`Y
`Y
`»_) Click an any wnrrl
`to see its definitiori
`elegy insiaritiyi
`
`
`Free Legal Information At FindLaw!
`www.FindLaw.com/DUI
`
`World English Dictionary
`friction (‘fril<j'an)
`‘E’;
`— n
`
`(‘z-}_/v'.\ViSUALTHESAUfiUS'
`«um
`friction I menu:
`c
`
`W,
`
`Exolore the Visual Thesaurus r»
`
`aponsonsa Resutts
`
`1. a resistance encountered when one body moves relative to
`another body with which it is in Contact
`2. the act, effect, or an instance of rubbing one object against
`another
`
`3. disagreement or conflict; discord
`4. ohonetics the hissing element of a speech sound, such as a
`fricative
`
`5. perfumed alcohol used on the hair to stimulate the scalp
`
`[C16: from French, from Latin fri'cti'c') a rubbing, from fricare to
`rub, rub down; related to Latin fr.-are to crumble]
`‘frictional
`
`-— adj
`‘frictionless
`_ ark‘
`
`

`
`hit 3//dictionar .referenc .com/browse/friction
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`U9/10001003239321 PM
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`— ad)’
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`Coiisrzs Engiii:
`' L‘? ii‘ Willi "
`
`"V0.7
`
`
`
`Word Origin & History
`
`friction
`1563, from L. frictionem (nom. frictio ) "a rubbing, rubbing down,"
`from fricare "to rub." Sense of "resistance to motion“ is from 1722;
`figurative sense of "disagreement, clash“ first recorded 1761.
`Jli ii Dui zgmt: H.1if)Bi
`
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`Medical Dictionary
`friction friction (frTk‘shori)
`I7.
`
`1. The rubbing of one object or surface against another.
`
`9
`
`A physical force that resists the relative motion or tenderici; to
`such motion of two bodies in contact.
`
`
`
`

`
`http://dictionary.reference.com/browse/friction
`
`U9/10.0010 03:39:21 PM
`
`Science Dictionary
`friction £‘113)(fr'il<'shan) Pronunciation Key
`A force on objects or substances in contact with each other that
`resists motion of the objects or substances relative to each other.
`[1 Static friction arises between two objects that are not in
`motion with respect to each other, as for example between a
`cement block and a wooden floor. It increases to counterbalance
`forces that would move the objects, up to a certain maximum level
`of force, at which point the objects will begin moving. It is
`measured as the maximum force the bodies will sustain before
`motion occurs. 0 Kinetic friction arises between bodies that are
`in motion with respect to each other, as for example the force that
`works against sliding a cement block along a wooden floor.
`Between two hard surfaces, the kinetic friction is usually somewhat
`lower than the static friction, meaning that more force IS required
`to set the objects in motion than to keep them in motion. See also
`dr g.
`
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`«
`
`Cultural Dictionary
`friction definition
`
`The resistance of an object to the medium through which or on
`which it is traveling, such as air, water, or a solid floor.
`
`Tins Arr
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`iicaii lieirtac
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`
`
`Famous Quotations
`friction
`
`"
`"One might call habit a moral friction: something that p..
`"Change means movement. Movement means friction. Only in..."
`"Children must eventually train their own children, and ..."
`"First, the cold friction of expiring sense
`Without..."
`
`"What opium IS instilled into all disaster? It shows for..."
`
`More Quotes
`
`Popular Subjects:
`
`

`
`hit
`
`://dictionar reference‘com/browse/friction
`
`D9r’1U/'2D1lJ 03:39:21 PM
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`Friction, Temperature Sc Wear
`www.remchem.com
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`ICL, manufactures non— estructive roadway test equipment.
`www.iiiLeriiuLioridIcybeirieLics.cuin
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` Subject > Physics > Physics I > Forces > Friction a
`Contact Force
`
`In real life an object which is moving overa horizontal surface does not continue with constant velocity
`when the accelerating force is removed. Instead the object slows down and eventually stops. The
`deceleration is caused by a frictional force between the object and the surface on which it travels. A
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`frictional force always acts to oppose the motion of an object over a surface and is an example of a
`contact force.
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`' Examples ofFriction
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`When we try to slide one object over another, we find that there is a force which opposes the motion.
`This force is called friction.
`
`Whenever there is relative motion ortwo surfaces In contact,there Ismctionai reslsiancewhen a body
`moves over another, it has to overcome friction. This needs energy. Hence, some energy is always
`wasted in overcoming frictionwhen two parts ofa machineryrub againsteach other heat is produced,
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`and the efficiency of the machine decreases. There will be a greaterwear and tear in the different parts
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`ifthe surfacesthatare in contact are rough,there is more friction. Hence to reducefriction, the surfaces
`in contact are kept smooth and polished. it is worth notingthat ifthe two surfaces in contact are of the
`same metal, the friction increases on polishing the two surfaces. This is whythe bearings and the axle
`are made ofdifferent metals.
`
`How is friction helpful?
`From what has been discussed above, it may appear that if there were no friction, our life would have
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`When we raise our heel again to take another forward pace, the friction prevents the front part ofthe
`shoe moving back. On account ofthe friction between the ground and the rubbertype of a bicycle, the
`latter can move forward.
`in the absence of friction between the wheels and ground, the wheels are
`unable to roll. This is why the wheels of bicycle and other vehicles are treaded to increase friction. To
`stop the bicycle, we use the opposing frictional force between the brake blocks and the wheel rim.
`When the driver applies the brakes of an automobile, the friction of the brake lining onthe brake drum
`slows down the wheels and enable him to bring the carto a stop. Friction holds a screw in wood. It also
`enables us to use nails to fix boards together. iffriction were eliminated, dishes would slide oflthe table
`unless the table were perfectly level. Thus without friction, our life would have been, in reality, very
`inconvenient.
`
`Types of Frictiori
`You must have noticed that when you have to slide a heavy box, it is easy to slide it once the box has
`started sliding. You may also have noticed that it is much more easy to roll a heavy drum than to slide it.
`This is because there are three types offriction.
`
`They are:
`
`"
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`'
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`‘
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`the Static Friction
`
`the Kinetic or Dynamic Friction, and
`
`the Rolling Friction.
`
`The friction that exists between the two surfaces in contact when there is no relative motion between
`them is called static friction.
`
`The force which makes the surface rust startto slide over another, is called limiting friction.
`
`The friction that exists between a surface sliding on another surface is called kinetic or dynamic friction.
`
`

`
`Friction: The Tortoise Always Wins!
`
`Preliminary Comments
`
`Friction is a part of our everyday life. Nearly every movement we make involves
`friction, and we have instinctively learned to take advantage of friction, or the lack of
`friction, since our childhood.
`
`Simple devices that rely on friction are everywhere around us.
`will help you see and appreciate the role of friction
`
`I hope that this workshop
`
`Scientists and Engineers have also been studying friction and its effects for a very long
`time. Engineers in particular have a “special” relationship with friction — a real “love-
`hate” relationship. For many applications, an engineer’s job is to combat friction and its
`effects through careful, clever design.
`In a few minutes we’ll talk about the wheel ~ the
`ancient engineer’s tremendously successful answer to the problems caused by friction.
`But in other cases, the engineer’s role is to use friction to best advantage — and there are
`some spectacular examples on this side of the “love-hate” line as well.
`
`In this program you’ll also learn that there is no practical way to eliminate. Like the
`tortoise, friction is always there, eating away at the energy you put into motion, and it
`will ultimately, sooner or later, cause the motion to stop. Ultimately, friction wins!
`
`Defining friction
`
`It is the resistance to the movement of
`Friction is the force that opposes sliding motion.
`one body i11 relation to another body with which it is in contact. For example if we try to
`slide a wooden block across a table then friction acts in the opposite direction to the
`movement of the block.
`
`Identifying the forces involved in friction
`
`Let’s talk about forces. Forces are pushes or pulls. (Nudge someone.) A nudge is a
`force. A tug of war is a balance of forces. Forces have direction. (Nudge again.) This
`nudge has direction along a horizontal like. Gravity is a force. Ask what direction the
`force of gravity acts in. Gravity pulls objects toward the earth. This is called weight.
`Weight is a force that acts “vertically,” or along the line of gravity.
`
`Now let’s look at this motionless block of wood on the table. The weight of the block is
`acting downward. Because the block is stationary, there must be an equal reactive force
`on the block from the table, acting upward, balancing the downward force. VVhat
`happens when the table isn’t there? The block falls downward under the force of
`gravity. Weight acts vertically down; the table reacts with equal force upward.
`
`Now let‘s push the block around. Pushing down on the block doesn't move it around on
`the table, although if we pushed hard enough — well the block could be forced right
`
`Support for Cornell Center for Materials Research is provided through NSF Grant DMR-O0 79992
`Copyright 2003 CCMR Educational Programs. All rights reserved.
`
` %
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`CCMR
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`through the table. We have to push (or apply a force) horizontally to get the block to
`move. A small force or push may not succeed in moving the block. WIIY? Friction is
`opposing the pushing force, like the table opposes the force of gravity. The weight of the
`block holds it to the table; the push and the resulting resisting force from friction is
`tangential to the surfaces of the block and the table. Tangential is an important modifier
`here.
`It comes from a root word meaning "to touch" and it implies that the frictional
`force acts perpendicular (or at r_igh_t angles) to the force holding the block to the table.
`
`Let’s follow this one more step. Let’s use a push to hold the block to a vertical surface.
`(Hold block to blackboard.) Now, if I try to slide the block up the wall, which way is
`friction acting? The frictional force acts tangentially to the push (force) holding the
`block to the wall, so now the frictional force is acting vertically. What happens if I take
`away the push holding the block to the wall?
`
`Let's review:
`-
`Friction is always a tangential force: it acts perpendicular to the forces that
`hold two surfaces together. Friction acts along the two surfaces.
`Friction always acts opposite to the motion of the surfaces.
`Take away the force holding the two surfaces together — there is no friction
`between the two surfaces.
`
`-
`-
`
`Friction is peculiar to the surfaces involved
`
`The friction depends upon the nature ofthe two surfaces in contact with each other. This
`seems natural, but it’s actually pretty interesting. Every situation is a little, or maybe a
`lot, different. If both the block and the table are highly polished (smooth) then there will
`be less friction than if the surfaces were rough. Have you seen the scene in westem
`("cowboy") films where the bartender slides a drink across the bar to the gunslinger
`at the other end? The glass moves smoothly across the bar coming to rest just in front of
`the "bad guy". The glass and table have smooth surfaces and so sliding is easy across the
`polished bar top - there is little friction.
`
`Let’s try it: Demonstrate glass sliding. I need a catcher!
`1. Slide glass
`2. Can we get it to stop?
`3. Suppose we‘re filming, time is short and Leonoardo DiCaprio the bartender is
`not managing to get the glass to stop in front of Ben Affleck, the bad guy.
`You‘re the set engineer, and the director wants you to “fix” the problem.
`What do you do‘?
`
`It's hard to
`But now consider two rough surfaces. (Use a block with sandpaper on table).
`move the block at all, let alone slide it because even when it starts moving it doesn't go
`far.
`In life, we encounter a range of surfaces from rough to smooth each with an
`associated friction.
`
`Let's use your friction boards to show that surfaces have different friction. Use the
`small set of weights to “pull’ on the small wooden blocks with hooks. Try to use the
`
`4%
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`3,3”
`
`Support for Cornell Center for Materials Research is provided through NSF Grant DMR—0O79992
`Copyright 2003 CCMR Educational Programs. All rights reserved.
`
`fl
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`

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`lightest combination of weights possible to just start the block moving across the friction
`board. Let’s try one together. Start with the small block on the smooth cardboard
`surface. Add the XXg mass and see if the block moves. Add a bit more. When you have
`settled on the lightest combination of masses, add up the grams and we’ll fill in this chart
`on the board. What's going on?
`
`Friction comes from surface characteristics
`
`Velcro Example: Let’s use an analogy to help us understand friction. We'll use Velcro to
`show how surfaces “stick" together. (Hand out Velcro and hand magnifiers) Does
`anyone here know how Velcro works? One side contains many small "loops," the
`other side contains many small hooks. Can you see the hooks and loops in your
`Velcro? Show me the "hook" side. (Check to see if they have found the hooks sides of
`the sample piece.) If you are very careful, you can see that the "hook" sides will also
`attach to other fabrics. Maybe some of you (like me) have found this out the hard way
`when your Velcro hook pad on your jacket accidentally attaches to your clothes, or
`maybe your hair!
`
`What happens with friction is at the atomic level. Much, much, much smaller than you
`can see.
`It's not quite like Velcro, but the nooks and crannies on the two surfaces can
`"get caught" and resist movement. Not exactly hooks and loops like Velcro, but more
`like the peaks and valleys (irregularities) get caught and prevent movement. Different
`surfaces have different kinds of peaks and valleys. So different surfaces generate
`different frictional resistance to sliding
`
`For an easy way to see this put your knuckles together like this (show) and try to slide
`your hands. Difficult? This happens on the atomic scale when surfaces are pressed
`together. You can see two essential facts about friction in this simple experiment.
`0
`First, you can see the way the irr