{VERSION 3 0 "APPLE_PPC_MAC" "3.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 }{CSTYLE "2D Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 0 0 0 0 } {PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Maple Output" 0 11 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 3 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 29 "Rebekah Boyd, Melinda Chau vin" }}{PARA 0 "" 0 "" {TEXT -1 19 "Page 97, problem 18" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 776 "When an object move s on a surface, it encounters a resistance force of friction. This fo rce has a magnitude of uN where u is the coefficient of friction and N is the magnitude of the normal force that the surface applies to the \+ object. Friction acts in opposition to motion, but cannot initiate mo tion. Suppose that an object of mass 30 kg is released from the top o f an inclined plane that iss inclined 30 degrees to the horizontal. (S ee picture in book on page 98). Assume that the gravitational force i s constant, air resistance is negligible, and the coefficient of frict ion u=0.2. Determine the equation of motion for the object as it slid es down the plane. If the top surface of the plane is 5 m long, what \+ is the velocity of the object when it reaches the bottom?" }}{PARA 0 " > " 0 "" {MPLTEXT 1 0 8 "restart:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "with(student):" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 473 "Since we are starting at the top of incline plane, we are having \+ to consider the forces that flow with the object as it slides down the plane and the forces that act on the object. Thus we have the normal force of N1+u*N2=m*dv/dt. N1 is represented by m*g*sin(Pi/6), where \+ m = mass, g = gravity , and Pi/6 is 30 degrees, and N2 is represented \+ by m*g*cos(Pi.6). As you can see the m's cancel and we are left with \+ the following equation after putting 0.2=u, g = 9.81m/s^2." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 51 "V:=(v,t)->(9.81*(sin(Pi/6))-(.2*9.81*(cos(P i/6))));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"VGR6$%\"vG%\"tG6\"6$%) operatorG%&arrowGF),&-%$sinG6#,$%#PiG#\"\"\"\"\"'$\"$\")*!\"#-%$cosGF0 $!%i>!\"$F)F)F)" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 284 "In this case, V represents the statement that velocity equals the sum of the forces on an object. Since the plane is inclined, the usual gravitational f orce is altered by the degree of incline. Since all of the above are \+ known, we found the numeric answer to simplify for use later." }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 49 "simplify(9.81*(sin(Pi/6))-(.2*9.81* (cos(Pi/6))));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#$\"+d\"ee?$!\"*" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 46 "(expression evaluated to get a num eric answer)" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "diff(v(t),t)=%;" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#/-%%diffG6$-%\"vG6#%\"tGF*$\"+d\"ee?$! \"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 116 "Using dsolve, we find the equation of velocity. This represents the velocity of the object as \+ is follows the plane." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "A:=(dsolve (%));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"AG/-%\"vG6#%\"tG,&F)$\"+d \"ee?$!\"*%$_C1G\"\"\"" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "F :=eval(A, _C1=0);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"FG/-%\"vG6#% \"tG,$F)$\"+d\"ee?$!\"*" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 261 "C1 is set to 0 because the object has no initial velocity; therefore the on ly forces acting on the object at this time will be gravity (in this c ase, \"pulling\" the block down the incline) and the opposing force of friction. Thus at t = 0, all forces are equal." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 33 "X:=dsolve((diff(x(t),t)=rhs(%)));" }}{PARA 11 "" 1 " " {XPPMATH 20 "6#>%\"XG/-%\"xG6#%\"tG,&*$)F)\"\"#\"\"\"$\"+z!HHg\"!\"* %$_C1G\"\"\"" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 214 "X represents the distance the object travels down the incline in terms of time squared . This number is found by integrating the velocity function. In the \+ case of our plane, the distance is known to be 5 meters. " }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "eval(X, _C1=0);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#/-%\"xG6#%\"tG,$*$)F'\"\"#\"\"\"$\"+z!HHg\"!\"*" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 114 "Again, the constant is set to 0 b ecause the object has at t = 0, the distance the object has traveled i s 0 meters." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "eval(%,x(t)=5);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#/\"\"&,$*$)%\"tG\"\"#\"\"\"$\"+z!HHg\" !\"*" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "solve(%, t);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6$$!+o5:m " 0 "" {MPLTEXT 1 0 22 "eval(F,t=1.766151068);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#/-%\"vG6#$\"+o5:m " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "11 0 0" 114 } {VIEWOPTS 1 1 0 1 1 1803 }