FACULTY OF ENGINEERING & TECHNOLOGYLAB REPORT EME 1016 APPLIED STATICSTRIMESTER 1 (2015/2016) EXPERIMRNT 1: FRICTIONN!": T"#$ S%&"% M"ID: 11'1(2)02(N!": T"" F#$ Y$ID: 11'1(2)(6*L+ $,-./: G,-./ 0DATE:2)/)/2015A+12,32The purpose of this experiment is to examine and compare the static and sliding frictionforces(Fsand Fk). We carried out one set of three friction tests as a function of area, weight,material, andforceofgravity.Wealsomadeacomparisonbetweentherollingandslidingfriction forces (Fr and Fk) as a function of weight.InSet oftheexperiment, wepulledawoodenbloc!sofvaryingsi"esacrosstheexperiment surface to determine the effects of the the surface area of the bloc!, the weight of thebloc!andthetypeofsurfaceonfrictionforce, Ff. InSet #, wepulledalargebloc!withadditional weightsacrosstheexperiment surfacetodeterminehowtheweight of anob$ectaffectsfrictionforce, Ffandtofindthecoefficient offriction, . InSet %, standrodswerealignednexttoeachothertoactastheexperimentsurface.Wepulledawoodenbloc!withadditional weightshori"ontallyandparallel totherodaxestodeterminetherollingfrictionforce, Fr and sliding friction force, Fk respectively. Wefoundthat the surface area didnot appear toaffectfrictionforce, Fandthecoefficient offriction, .Weight affectsfrictionforce, Ffbut doesnot affectcoefficient offriction, .&owever,thetypeofmaterialsincontact directlyaffectsfrictionforce, Fand,coefficient of friction . The type of surface produced the largest percentage difference in valuesof coefficient of friction , '(.)* for the change in coefficient of static friction,sand )+.#*for the change in coefficient of sliding friction, k.I#2,-4.32&-#The purpose of this experiment is to examine static and sliding friction forces (Fs and Fk)and the factors that affect it. The factors that are examined within this experiment are the surfaceareaoftheob$ect, thetypeofsurfacesincontactwithoneanother,andtheforceofgravity(weight). ,ll of these will be tested and compared to see how they affect the value of frictionforces.-riction is a force that always opposes the motion of an ob$ect. ,ccording to velocity,friction may be classified into static friction force, Fs(when velocity . /) and sliding frictionforce, Fk (when velocity 0 /). Static friction force, Fs is a force between two ob$ects that are notmoving relative to one another. -or example, an ob$ect resting on a slope, but not sliding downthe slope, is !ept in its position by this friction.Static friction force, Fsmust be overcome tocause an ob$ect to move across a surface. 1nce enough force has been applied to an ob$ect, it willbegin to slide across a surface and sliding friction force, Fk will then act on the ob$ect. Slidingfriction force, Fkoccurs when two ob$ects are moving relative to one another with one ob$ectsliding across the surface of the other and it opposes the motion of the ob$ect. 2oth types offriction are described by different coefficients. These values are !nown as thecoefficients ofstatic and sliding friction (s and k) respectively and they are dimensionless.34 The coefficientofstatic friction, sis usually higher thancoefficientof sliding friction, k.Coefficients offriction, is a measure of how easily one ob$ect moves in relationship to another. When youhave a high coefficient of friction, , you have a lot of friction between the materials.5very ob$ect in the universe that hasmass thatexerts a gravitational pull, orforce,onevery other mass. The si"e of the pull depends on the masses of the ob$ects. The experiment usesthe force of gravity (weight) in order to find the maximumstatic friction force, Fson an ob$ect before it turns into sliding friction force, Fk. This will help in the understanding ofhow the forces will either increase or decrease due to the mass of the ob$ect.F&$.," 1, small bloc! was placed on the experiment surface as shown in -igure . When no forceis applied to the bloc!, the bloc! remains at a stationary position. ,t this position, the normal force, Nfof bloc! is e6ual to its own weight, W.Whenapullingforce, Fpisappliedtothebloc!parallel tothehori"ontalsurface, afriction force, Ff is acting in an opposite direction to the pulling force, Fp. If Fpis smaller thanFf, the bloc! is not moving. If Fp is e6ual to Ff, the bloc! is about to move3%4. If Fp is greater thanFf, the bloc! is moving in the direction of Fp with acceleration.3#4 The resultant force is givenbythe formula7Resultant force=FpFf,fter that, we can calculate the coefficients of static and sliding friction (s and k) usingthe formulas7 = FfNf = FpWs= FsWk=FkwTofind thefriction force,Ffwemeasurestaticfrictionforce,Fsbynotingthe scalereading on spring balance $ust before the bloc! slides.Static friction force, Fshas values from"ero to its maximum value.When the bloc! starts to move and static friction force, Fs has amaximumvalue. 1ncethebloc!startsmovingthefrictionisslidingfrictionforce, Fki.e.!inetic friction. We measure sliding friction force, Fkby continuing to pull the bloc! at constanta speed. ,fter getting the values of static andsliding friction forces(Fsand Fk), we can nowcompare with aspect to each factor to find out which factor causes the greatest effect on frictionforce, Ff. The e6uation below is used to calculate the percentage difference7Differenc e=Value1Value2F&$.," 2Average=Value 1+Value22Percentagedifference=(|DifferenceAverage |)100O+5"32&6"1. To determine the static and sliding friction forces (Fs and Fk)as function of7a) ,reab) Weightc) 8aterialand then to compare the friction forces (Fs and Fk) for different areas, weights, and materials.#. To compare rolling and sliding friction forces (Fr and Fk) as a function of weight.%. To determine the friction coefficient of friction, in rolling case.A//,2.1. 1ne set of four weights, /.!g, /.#!g, /.(!g and!g with hoo!.#. 1ne set of six stand rods with length, //mm and diameter, #mm.%. 1ne set of three spring balances 9, (9 and /9.:. 1ne pair of wooden bloc!s with one of the sides covered with rubber.

F&$.," (: 17$8 0957$8 0927$ #4 0917$ :"&$%21 :&2% %--7F&$.," ': S2#4 ,-41F&$.," 5: S/,$ +;#3"1 1N8 5N8 10NF&$.," 6: (R"=", 2- F&$9*)P,-3"4.,": The stand rods are laid next to each other and the large bloc! is placed on the rods with its plastic side down.# The hori"ontal pulling force is measured by maintaining a uniform motion on the rolling rodsas. This is the rolling friction force, Fr9% The weight of the bloc! is increased by adding in turn the weights /.!g, /.#!g, /.(!g and ./!g. The measurements are repeated.: The bloc! are aligned parallel to the rod axes. The sliding friction force, Fk is measured.( The graph of sliding friction force and rolling friction force as a function of the force of gravity is plotted.F&$.," *: M"1.,$ 2%" ,-;;$ #4 1;&4$ =,&32&-# =-,3" 1=.#32&-# -= 2%" =-,3" -= $,6&2>9R"1.;21 #4 O+1",62&-#1:;onstants7 (i) Acceleration due gravity , g=9.81ms2(ii) Weigt of 0.1kg mass=(0.19.81)N 0.981N(iii) Weigt of 0.2kg mass=(0.29.81) N 1.962N(iv) Weigt of 0.5kg mass=(0.59.81) N 4.905 N(v) Weigt of 0.8kg mass=(0.89.81) N 7.848N(vi) Weigt of 1.0kg mass=(1.09.81)N 9.810 N,rea of all three sides of the large bloc! are the same.Weigt of "lock wit0.1kg mass=( 3.2239+0.981) N 4.2049 NWeigt of "lock wit0.2kg mass=( 3.2239+1.962) N 5.1859N Weigt of "lock wit0.5kg mass=( 3.2239+4.905) N 8.1289NWeigt of "lock wit0.8 kgmass=(3.2239+7.848) N 11.0719 N Weigt of "lock wit1.0kg mass=( 3.2239+9.810) N 13.0339N-ormula to calculate coefficient of friction, ?7=PullingForceWeigt of #"$ect=FpWSet 7 Static and sliding friction forces as a function of the area, the weight and the material. (i)7 8easuring -s, -!, ?s and ?! using the small bloc! with its narrow wooden side down.8easurement, (9) ;oefficient of -riction, ?I II III I@ @ ,verageStatic -riction -orce, -s (9) /.+/ /.(/ /.(# /.(/ /.() /.(: /.#A/ASliding -riction -orce, -! (9) /.%/ /.%# /.%# /.%: /.%: /.%# /.'#:T+;" 1 (ii)7 8easuring -s, -!, ?s and ?! using the small bloc! with its wide wooden side down.8easurement, (9);oefficient of -riction,?I II III I@ @ ,verageStatic -riction -orce, -s (9)/.(//.'//.+//.'//.'//.+: /.%::)Sliding -riction -orce, -! (9)/.(//.(//.://.(//.(//.:) /.#()+T+;" 2 (iii)7 8easuring -s, -!, ?s and ?! using the small bloc! with its rubber side down.8easurement, (9) ;oefficient of -riction, ?I II III I@ @ ,verageStatic -riction -orce, -s (9) .#/ .%/ .#/ ./ .// .+ /.+#:ASliding -riction -orce, -! (9) /.'/ /.)/ /.'/ /.)/ /.'/ /.': /.%A)+T+;" ( (iv)7 8easuring -s, -!, ?s and ?! using the large bloc! with its wooden side down.8easurement, (9);oefficient of -riction,?I II III I@ @ ,verageStatic -riction -orce, -s (9) /.A/ ./ /.A/ ./ .// .// /.%/#Sliding -riction -orce, -! (9) /.+/ /.'/ /.'/ /.)/ /.'/ /.'/ /.#'T+;" ' (v)7 8easuring -s, -!, ?s and ?! using the large bloc! with its rubber side down.8easurement, (9);oefficient of -riction,?I II III I@ @ ,verageStatic -riction -orce, -s (9) #.:/ #.%/ #.// #.#/ #.#/ #.## /.+))'Sliding -riction -orce, -! (9) .'/ .)/ .+/ .)/ .A/ .'+ /.(:+/T+;" 5 (a) -riction -orce and ;oefficient of -riction as a function of ,reaa (i) ;onstant variable7 8aterial (Wood) and Weight (.)(+%9BSmall bloc!) ,rea, (m#) Static -riction -orce, -s (9) Sliding -riction -orce, -! (9)/.//%('/ /.(: /.%#/.//+A/% /.+: /.:)T+;" 6/.//%/// /.//%(// /.//:/// /.//:(// /.//(/// /.//((// /.//+/// /.//+(// /.//'/// /.//'(///.%//.%(/.://.:(/.(//.((/.+//.+(/.'/G,/% -= F,&32&-# F-,3"8 F 619 A,"A,"8 (!2)F8 (N)G,/% 1a (ii) ;onstant variable7 8aterial (Wood) and Weight (.)(+%9BSmall bloc!) ,rea, (m#) ;oefficient of Static -riction, ?s;oefficient of Sliding -riction, ?! /.//%('/ /.#A/A /.'#:/.//+A/% /.%::) /.#()+T+;" )/.//%/// /.//%(// /.//:/// /.//:(// /.//(/// /.//((// /.//+/// /.//+(// /.//'/// /.//'(///.(///.#////.#(///.%////.%(///.:///G,/% -= C-"==&3&"#2 -= F,&32&-#8 ? 619 A,"A,"8 (!2)?G,/% 2 (b) -riction -orce and ;oefficient of -riction as a function of Weightb (i) ;onstant variable7 8aterial (Wood) and ,rea (/.//'/#/m#)Weight, W (9) Static -riction -orce, -s (9) Sliding -riction -orce, -! (9).)(+% /.+: /.:)%.##%A .// /.'/T+;" 0.+ .) # #.# #.: #.+ #.) % %.# %.:/.:/.(/.+/.'/.)/.A

.G,/% -= F,&32&-# F-,3"8 F 619