{VERSION 5 0 "SUN SPARC SOLARIS" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 40 "Math 2250 Maple Project 2, October 2002" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 95 "NAME _____________________________________________ CLASS TIME _____________ SECTION 2250- ___" }}{PARA 0 "" 0 "" {TEXT -1 0 " " }}{PARA 0 "" 0 "" {TEXT -1 99 "There are six (6) problems in this pr oject. You are expected to answer the questions A, B, C , ... " }} {PARA 0 "" 0 "" {TEXT -1 110 "associated with each problem. The origi nal worksheet \"project2-fall-2002.mws\" is a template for the solutio n;" }}{PARA 0 "" 0 "" {TEXT -1 104 " you must fill in the code and all comments. Sample code can be copied with the mouse. Please use pencil " }}{PARA 0 "" 0 "" {TEXT -1 85 " freely to annotate the worksheet and to clarify any code or figure presented herein." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 96 "The problem headers for t he Fall 2002 revision of David Eyre's project (original was year 2000) ." }}{PARA 0 "" 0 "" {TEXT -1 494 " __________ 2.1. OVERDAMPED FREE OS CILLATIONS. The first four problems study the\n __ ________2.2. UNDERDAMPED FREE OSCILLATIONS. simplest linear model for x(t).\n __________2.3. UNDAMPED FORCED OSCILLATIONS \+ (c=0).\n __________2.4. DAMPED FORCED OSCILLATIONS (c>0).\n __________ 2.5. LARGE SUSTAINED OSCILLATIONS. This is the s econd, nonlinear model.\n __________2.6. MCKENNA NON-HOOKES LAW CABLE \+ MODEL. This is the third, nonlinear model.\n" }}{PARA 0 "" 0 "" {TEXT -1 1 " " }}{PARA 0 "" 0 "" {TEXT -1 44 "2.1. PROBLEM (OVERDAMPE D FREE OSCILLATIONS)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 " " {TEXT -1 76 "FREE OSCILLATIONS. Consider the general problem of free linear oscillations\n" }}{PARA 0 "" 0 "" {TEXT -1 63 " m x' ' + c x' + k x=0,\n x(0)=x0, x'(0)=v0," }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 69 " where m=1, k=16 and c is a non-negative constant. The symbols " }}{PARA 0 "" 0 "" {TEXT -1 76 " x0 and v0 are the initial position and initial velocity, r espectively.\n" }}{PARA 0 "" 0 "" {TEXT -1 94 " A. Suggest a value \+ for parameter c > 0 so that the free oscillations are overdamped. Thi s" }}{PARA 0 "" 0 "" {TEXT -1 108 " value will be used in item s B, C, D below. Check your answer by solving the characteristic equat ion" }}{PARA 0 "" 0 "" {TEXT -1 68 " using Maple's \"solve\" c ommand (example: solve(r^2-1=0,r);)." }}{PARA 0 "" 0 "" {TEXT -1 4 " \+ " }}{PARA 0 "" 0 "" {TEXT -1 100 " B. Use x(0)=1 and x'(0)= -2 fo r the initial conditions and Maple's \"dsolve\" to find the explicit" }}{PARA 0 "" 0 "" {TEXT -1 95 " real solution x(t). Plot the so lution x(t) for t=0 to t=5 using Maple's \"plot\" command." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 107 " C. Suggest n ew values for x(0) and x'(0) such that the solution is non-negative, i ncreases near t=0 but" }}{PARA 0 "" 0 "" {TEXT -1 114 " eventua lly decreases with limit zero at t=infinity. Find the explicit solutio n and plot it for t=0 to t=5." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 107 " D. Suggest new values for x(0) and x '(0) such that the solution changes sign exactly once on t>0, then " } }{PARA 0 "" 0 "" {TEXT -1 96 " decreases to zero at t=infinity . Find the explicit solution and plot it for t=0 to t=5." }}{PARA 0 " " 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 121 "EXAMPLE(Wrong par ameters! Change it!)\nde:=3*diff(x(t),t,t)+1.5*diff(x(t),t)+4*x(t)=0: \+ # Define the differential equation" }}{PARA 0 "" 0 "" {TEXT -1 273 "i c:=x(0)=1,D(x)(0)= -2: # Define the in itial conditions\ndsolve(\{de,ic\},x(t),method=laplace); \+ # Symbolically solve for x(t)\nX:=unapply(rhs(%),t): \+ # Capture the symbolic answer as a function X(t)" }} {PARA 0 "" 0 "" {TEXT -1 80 "plot(X(t),t=0..5); \+ # Plot the solution" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.1-A" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.1-B" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 6 "#2.1-C" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.1-D" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 44 "2.2. PROBLEM (UNDERDAMPED FREE OSCILLATIO NS)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 68 "FR EE OSCILLATIONS. Consider the problem of free linear oscillations\n" } }{PARA 0 "" 0 "" {TEXT -1 61 " m x'' + c x' + k x=0,\n \+ x(0)=0, x'(0)=1," }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 74 " where m=2, c=4 and k is a non-negative constant . The underdamped case" }}{PARA 0 "" 0 "" {TEXT -1 75 " is studied her e, for which the solution x(t) has at most one oscillation. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 72 " A. Find a \+ parameter value k > 5 so that the solution x(t) changes" }}{PARA 0 " " 0 "" {TEXT -1 77 " sign infinitely many times and decays to \+ zero at t=infinity. Display" }}{PARA 0 "" 0 "" {TEXT -1 58 " t he value of k and the exact symbolic solution." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 80 " B. Plot the exact sym bolic solution x(t) from t=0 to t=5. Estimate from the " }}{PARA 0 "" 0 "" {TEXT -1 52 " graph the decimal value of the pseudoperiod. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 89 " C . Use the solution formula for x(t) from 2.2.A to calculate the exact pseudoperiod." }}{PARA 0 "" 0 "" {TEXT -1 77 " Verify that y our answer is consistent with the estimate of 2.2.B. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 39 "#2.2-A Define k, then solve and plot." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.2-B" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "#2.2-C " }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 49 "2.3. PROBLEM (UNDAMPED FORCED OSCILLATIONS (c=0))" }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 57 "FORCED LI NEAR OSCILLATIONS. Consider the forced problem\n" }}{PARA 0 "" 0 "" {TEXT -1 103 " x'' + 1.5625 x = 10 cos(wt),\n x(0)=0, x'(0 )=0,\n\n where w is a non-negative constant." }}{PARA 0 "" 0 "" {TEXT -1 2 " " }}{PARA 0 "" 0 "" {TEXT -1 76 " A. Choose w=3.75, so that the forcing frequency w is 3 times larger " }}{PARA 0 "" 0 "" {TEXT -1 76 " than the natural frequency w0=1.25. Solve fo r x(t) using dsolve()." }}{PARA 0 "" 0 "" {TEXT -1 77 " Plot \+ the solution x(t) on a suitable interval in order to show the " }} {PARA 0 "" 0 "" {TEXT -1 48 " global behavior of the solutio n x(t)." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 108 " B. The solution x(t) is the sum of two functions, one of peri od 2Pi/w and the other of period 2Pi/w0." }}{PARA 0 "" 0 "" {TEXT -1 72 " Approximate the period of x(t) by examining the graph \+ in 2.2.A." }}{PARA 0 "" 0 "" {TEXT -1 1 " " }}{PARA 0 "" 0 "" {TEXT -1 95 " C. Calculate the period of x(t) from the solution formula \+ (see page 341 for how to do this" }}{PARA 0 "" 0 "" {TEXT -1 72 " \+ in general). Verify that your answer is consistent with 2.3.B." } }{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 85 " D. S uggest a value for the forcing frequency w so that the oscillations \+ exhibit" }}{PARA 0 "" 0 "" {TEXT -1 55 " resonance. Show reso nant behavior on a graph." }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" } {TEXT -1 2 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "#2.3-A " } }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "#2.3-B " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "#2.3-C " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "#2.3-D " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 " " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 47 "2.4. PROBLEM (DAMPED FORCED O SCILLATIONS (c>0))" }}{PARA 0 "" 0 "" {TEXT -1 31 " Consider the for ced problem\n" }}{PARA 0 "" 0 "" {TEXT -1 60 " x'' + 2 x' + 21 x \+ = 10cos(t),\n x(0)=0, x'(0)=0,\n" }}{PARA 0 "" 0 "" {TEXT -1 59 " A. Solve for x(t) and plot the solution on t=0 to t=15." }}{PARA 0 "" 0 "" {TEXT -1 5 " " }}{PARA 0 "" 0 "" {TEXT -1 107 " B. E xtract the steady-state solution xss(t) from the solution x(t) of 2.4. A. Plot x(t) on t=0 to t=15." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 97 " C. Consider the equation x'' + c x' + 21 x \+ = 5cos(wt), where c=2, c=1 or c=1/2. Compute the" }}{PARA 0 "" 0 "" {TEXT -1 107 " amplitude function C(w) of xss(t) [page 346] fo r these three equations, then plot for w=0 to w=20 " }}{PARA 0 "" 0 " " {TEXT -1 59 " the three amplitude graphs on a single set of a xes." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 103 " D. Consider the equation x'' + c x' + 21 x = 10 cos(wt). For each \+ case c=2, c=1, c=1/2, print the " }}{PARA 0 "" 0 "" {TEXT -1 96 " \+ values w*, C* where C*=C(w*)=max \{C(w) : 0 <= w <= 20\}. The \+ three data pairs should " }}{PARA 0 "" 0 "" {TEXT -1 89 " show that C* becomes larger as c tends to zero. SAVE YOUR MAPLE FILE FREQ UENTLY" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 108 " Maple Hint: Use Maple's mouse interface on the graphic o f Part C. Specifically, click on a possible" }}{PARA 0 "" 0 "" {TEXT -1 104 " maximum (horizontal tangent) in the graph to display \+ the values w*, C* on the screen. Copy the" }}{PARA 0 "" 0 "" {TEXT -1 25 " values on paper." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 66 "EXAMPLE(Beware! Wrong values!)\nF:=15: m: =1: k:=25: c:='c': w:='w':" }}{PARA 0 "" 0 "" {TEXT -1 88 "C:=(w,c)->F /sqrt((k-m*w*w)^2+(c*w)^2):\nplot(\{C(w,4),C(w,3),C(w,2)\},w=0..15,col or=black);" }}{PARA 0 "" 0 "" {TEXT -1 47 "Cmax:=evalf(maximize(C(w,2) ,w=0..20,location));" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "#2.4-A Solve and plot." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 30 "#2.4-B Define and plot xss(t)." }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 51 "#2.4-C Plot C(w), three grap hics on one set of axes" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 42 " #2.4-D Table of six data values for w*, C*" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 43 "2.5. PROBLE M (LARGE SUSTAINED OSCILLATIONS)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 361 "NONLINEAR MODEL WITH GEOMETRY INCLUDED. \nConsider the nonlinear, forced, damped oscillator equation for torsi onal motion, with bridge geometry included,\n\n x'' + 0.05 x' + 2.4 sin(x)cos(x) = 0.06 cos (12 t/10) ,\n x(0) = x0, x'(0) = v0\n\nan d its corresponding linearized equation\n\n x'' + 0.05 x' + 2.4 x = \+ 0.06 cos (12 t/10) , \n x(0) = x0, x'(0) = v0.\n" }}{PARA 0 "" 0 " " {TEXT -1 84 "The spring-mass system parameters are m=1, c = 0.05, k = 2.4, w = 1.2 , F = 0.06." }}{PARA 0 "" 0 "" {TEXT -1 116 "Maple c ode used to solve and plot the solutions appears below.\n\n # WARNIN G: set the parameters on the second line!" }}{PARA 0 "" 0 "" {TEXT -1 58 " m:=1: F := 0.06: w := 1.2: m:=1: c:= 0.05: k:= 2.4: " }} {PARA 0 "" 0 "" {TEXT -1 29 " x0:=0: v0:=0: a:=0: b:=50:" }}{PARA 0 "" 0 "" {TEXT -1 198 " deNonLinear:= m*diff(x(t),t,t) + c*diff(x(t), t) + k*sin(x(t))*cos(x(t)) = F*cos(w*t):\n deLinear:= m*diff(x(t),t, t) + c*diff(x(t),t) + k*x(t) = F*cos(w*t):\n with(DEtools): opts:=s tepsize=0.1:" }}{PARA 0 "" 0 "" {TEXT -1 158 " DEplot(deNonLinear,x( t),t=a..b,[[x(0)=x0,D(x)(0)=v0]],opts,title='NonLinear');\n DEplot(d eLinear,x(t),t=a..b,[[x(0)=x0,D(x)(0)=v0]],opts,title='Linear');\n" }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 103 " A. L et x0=0, v0=0. Plot the solutions of the linear and nonlinear equat ions from t=160 to t=260." }}{PARA 0 "" 0 "" {TEXT -1 79 " The se plots represent the steady state solutions of the two equations." } }{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 103 " B. L et x0=1.2, v0=0. Plot the solutions of the linear and nonlinear equa tions from t=220 to t=320." }}{PARA 0 "" 0 "" {TEXT -1 108 " The se plots represent the steady state solutions of the two equation, wit h new starting value x0=1.2." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 90 " C. Argue in a sentence why the two linear \+ plots have to be identical, based upon the " }}{PARA 0 "" 0 "" {TEXT -1 88 " superposition formula x(t)=xh(t)+xss(t), even though \+ the homogeneous solution " }}{PARA 0 "" 0 "" {TEXT -1 103 " x h(t) is different for the two plots. Please include a discussion of th e amplitude of xh(t) " }}{PARA 0 "" 0 "" {TEXT -1 44 " on th e corresponding t-interval. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 93 " D. Determine the ratio of the appare nt amplitudes (a number > 1) for the nonlinear plots" }}{PARA 0 "" 0 " " {TEXT -1 92 " and explain why \"large sustained oscillations \" is an appropriate description of the" }}{PARA 0 "" 0 "" {TEXT -1 41 " nonlinear steady-state behavior." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.5-A" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2.5-B" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "#2 .5-C" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 55 "2.6. PROBLEM. ( MCKENNA'S NON-HOOKE'S LAW CABLE \+ MODEL)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 68 " MCKENNA'S NON-HOOKE'S LAW CABLE MODEL FOR THE TACOMA NARROWS BRIDGE " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 73 "The m odel of McKenna studies the bridge with a nonlinear, forced, damped " }}{PARA 0 "" 0 "" {TEXT -1 78 "oscillator equation for torsional motio n that accounts for the non-Hooke's law" }}{PARA 0 "" 0 "" {TEXT -1 75 "cables coupled to the equations for vertical motion. The equation s in this" }}{PARA 0 "" 0 "" {TEXT -1 78 "case couple the torsional mo tion with the vertical motion. The equations are:" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 63 " x'' + c x' - k G(x,y) = F sin wt, x(0) = x0, x'(0) = x1," }}{PARA 0 "" 0 "" {TEXT -1 63 " y'' + c y' + (k/3) H(x,y) = g , y(0) = y0, y'(0) = y1," }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 81 "where x(t ) is the torsional motion and y(t) is the vertical motion. The functio ns" }}{PARA 0 "" 0 "" {TEXT -1 74 "G(x,y) and H(x,y) are the models of the force generated by the cable when " }}{PARA 0 "" 0 "" {TEXT -1 81 "it is contracted and stretched. Below is sample code for writing t he differential" }}{PARA 0 "" 0 "" {TEXT -1 77 "equations and for plot ting the solutions. It is ready to copy with the mouse." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 276 "with(DEtools): \+ \nw := 1.3: F := 0.05: f(t) := F*sin(w*t): \nc := 0.01: \+ k1 := 0.2: k2 := 0.4: g := 9.8: L := 6: \nSTEP:=x ->piecewise(x<0,0,1):\nfp(t) := y(t)+(L*sin(x(t))):" }}{PARA 0 "" 0 " " {TEXT -1 384 "fm(t) := y(t)-(L*sin(x(t))):\nSm(t) := STEP(fm(t))*fm( t):\nSp(t) := STEP(fp(t))*fp(t):\nsys := \{ \n diff(x( t),t,t) + c*diff(x(t),t) - k1*cos(x(t))*(Sm(t)-Sp(t))=f(t),\n diff (y(t),t,t) + c*diff(y(t),t) + k2*(Sm(t)+Sp(t)) = g\}:\nic := [[x(0)=0, D(x)(0)=0, y(0)=27.25, D(y)(0)=0]]:\nvars:=[x(t),y(t)]: \nopts:=ste psize=0.1: \nDEplot(sys,vars,t=0..300,ic,opts,scene=[t,x]);\n" }} {PARA 0 "" 0 "" {TEXT -1 96 "The amazing thing that happens in this si mulation is that the large vertical oscillations take " }}{PARA 0 "" 0 "" {TEXT -1 80 "all the tension out of the springs and they induce l arge torsional oscillations." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 86 " A. TORSIONAL OSCILLATION PLOT. Get the sample \+ code above to produce the plot of x(t) " }}{PARA 0 "" 0 "" {TEXT -1 39 " [that's what scene=[t,x] means]. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 97 " B. Estimate the number of degr ees the roadway oscillates based on the plot; recall that x in the" }} {PARA 0 "" 0 "" {TEXT -1 95 " plot is reported in radians. Comment on the agreement of this result with historical data." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 95 " Hint: Average t he five largest amplitudes in the plot to find an average maximum ampl itude" }}{PARA 0 "" 0 "" {TEXT -1 73 " for t=0 to t=300. Convert t o degrees using Pi radians = 180 degrees." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 81 " C. VERTICAL OSCILLATION PLOT. Mod ify the DEplot code to scene=[t,y] and plot the" }}{PARA 0 "" 0 "" {TEXT -1 98 " oscillation y(t) on t=0 to t=300. The plot is suppo sed to show 30-foot vertical oscillations" }}{PARA 0 "" 0 "" {TEXT -1 92 " that dampen to 7-foot vertical oscillations after 300 second s.Comment on the agreement" }}{PARA 0 "" 0 "" {TEXT -1 98 " betwe en these oscillation results and the historical data for Tacoma Narrow s, especially the" }}{PARA 0 "" 0 "" {TEXT -1 66 " visual data pr esent in the film clip of the bridge disaster." }}{PARA 0 "" 0 "" {TEXT -1 6 " " }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "#2.6-A Torsional plot t-versus-x" } }}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 47 "#2.6-B Roadway oscillatio n estimate in degrees" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 "#2 .6-C Vertical plot t-versus-y" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "30 0 0" 31 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 } {PAGENUMBERS 0 1 2 33 1 1 }