// Numbas version: finer_feedback_settings {"name": "VM7: Symmetric parabolic loading", "extensions": ["jsxgraph", "polynomials", "quantities"], "custom_part_types": [{"source": {"pk": 19, "author": {"name": "William Haynes", "pk": 2530}, "edit_page": "/part_type/19/edit"}, "name": "Engineering Accuracy with units", "short_name": "engineering-answer", "description": "
A value with units marked right if within an adjustable % error of the correct value. Marked close if within a wider margin of error.
", "help_url": "", "input_widget": "string", "input_options": {"correctAnswer": "siground(settings['correctAnswer'],4)", "hint": {"static": true, "value": ""}, "allowEmpty": {"static": true, "value": true}}, "can_be_gap": true, "can_be_step": true, "marking_script": "mark:\nswitch( \n right and good_units and right_sign, add_credit(1.0,'Correct.'),\n right and good_units and not right_sign, add_credit(settings['C2'],'Wrong sign.'),\n right and right_sign and not good_units, add_credit(settings['C2'],'Correct value, but wrong or missing units.'),\n close and good_units, add_credit(settings['C1'],'Close.'),\n close and not good_units, add_credit(settings['C3'],'Answer is close, but wrong or missing units.'),\n incorrect('Wrong answer.')\n)\n\ninterpreted_answer:\nqty(student_scalar, student_units)\n\n\n\ncorrect_quantity:\nsettings[\"correctAnswer\"]\n\n\n\ncorrect_units:\nunits(correct_quantity)\n\n\nallowed_notation_styles:\n[\"plain\",\"en\"]\n\nmatch_student_number:\nmatchnumber(studentAnswer,allowed_notation_styles)\n\nstudent_scalar:\nmatch_student_number[1]\n\nstudent_units:\nreplace_regex('ohms','ohm',\n replace_regex('\u00b0', ' deg',\n replace_regex('-', ' ' ,\n studentAnswer[len(match_student_number[0])..len(studentAnswer)])),\"i\")\n\ngood_units:\ntry(\ncompatible(quantity(1, student_units),correct_units),\nmsg,\nfeedback(msg);false)\n\n\nstudent_quantity:\nswitch(not good_units, \n student_scalar * correct_units, \n not right_sign,\n -quantity(student_scalar, student_units),\n quantity(student_scalar,student_units)\n)\n \n\n\npercent_error:\ntry(\nscalar(abs((correct_quantity - student_quantity)/correct_quantity))*100 \n,msg,\nif(student_quantity=correct_quantity,0,100))\n \n\nright:\npercent_error <= settings['right']\n\n\nclose:\nright_sign and percent_error <= settings['close']\n\nright_sign:\nsign(student_scalar) = sign(correct_quantity)", "marking_notes": [{"name": "mark", "description": "This is the main marking note. It should award credit and provide feedback based on the student's answer.", "definition": "switch( \n right and good_units and right_sign, add_credit(1.0,'Correct.'),\n right and good_units and not right_sign, add_credit(settings['C2'],'Wrong sign.'),\n right and right_sign and not good_units, add_credit(settings['C2'],'Correct value, but wrong or missing units.'),\n close and good_units, add_credit(settings['C1'],'Close.'),\n close and not good_units, add_credit(settings['C3'],'Answer is close, but wrong or missing units.'),\n incorrect('Wrong answer.')\n)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "qty(student_scalar, student_units)\n\n"}, {"name": "correct_quantity", "description": "", "definition": "settings[\"correctAnswer\"]\n\n"}, {"name": "correct_units", "description": "", "definition": "units(correct_quantity)\n"}, {"name": "allowed_notation_styles", "description": "", "definition": "[\"plain\",\"en\"]"}, {"name": "match_student_number", "description": "", "definition": "matchnumber(studentAnswer,allowed_notation_styles)"}, {"name": "student_scalar", "description": "", "definition": "match_student_number[1]"}, {"name": "student_units", "description": "Modify the unit portion of the student's answer by
\n1. replacing \"ohms\" with \"ohm\" case insensitive
\n2. replacing '-' with ' '
\n3. replacing '°' with ' deg'
\nto allow answers like 10 ft-lb and 30°
", "definition": "replace_regex('ohms','ohm',\n replace_regex('\u00b0', ' deg',\n replace_regex('-', ' ' ,\n studentAnswer[len(match_student_number[0])..len(studentAnswer)])),\"i\")"}, {"name": "good_units", "description": "", "definition": "try(\ncompatible(quantity(1, student_units),correct_units),\nmsg,\nfeedback(msg);false)\n"}, {"name": "student_quantity", "description": "This fixes the student answer for two common errors.
\nIf student_units are wrong - replace with correct units
\nIf student_scalar has the wrong sign - replace with right sign
\nIf student makes both errors, only one gets fixed.
", "definition": "switch(not good_units, \n student_scalar * correct_units, \n not right_sign,\n -quantity(student_scalar, student_units),\n quantity(student_scalar,student_units)\n)\n \n"}, {"name": "percent_error", "description": "", "definition": "try(\nscalar(abs((correct_quantity - student_quantity)/correct_quantity))*100 \n,msg,\nif(student_quantity=correct_quantity,0,100))\n "}, {"name": "right", "description": "", "definition": "percent_error <= settings['right']\n"}, {"name": "close", "description": "Only marked close if the student actually has the right sign.
", "definition": "right_sign and percent_error <= settings['close']"}, {"name": "right_sign", "description": "", "definition": "sign(student_scalar) = sign(correct_quantity) "}], "settings": [{"name": "correctAnswer", "label": "Correct Quantity.", "help_url": "", "hint": "The correct answer given as a JME quantity.", "input_type": "code", "default_value": "", "evaluate": true}, {"name": "right", "label": "% Accuracy for right.", "help_url": "", "hint": "Question will be considered correct if the scalar part of the student's answer is within this % of correct value.", "input_type": "code", "default_value": "0.2", "evaluate": true}, {"name": "close", "label": "% Accuracy for close.", "help_url": "", "hint": "Question will be considered close if the scalar part of the student's answer is within this % of correct value.", "input_type": "code", "default_value": "1.0", "evaluate": true}, {"name": "C1", "label": "Close with units.", "help_url": "", "hint": "Partial Credit for close value with appropriate units. if correct answer is 100 N and close is ±1%,Students must derive the shear and bending moment functions for beam loaded with a parabolic distributed load described with a loading function. Diagrams are given, but the students must derive the equations by integration.
", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "statement": "A {qty(2b, units[0])} long, simply-supported beam is subjected to a symmetrical parabolic loading, where
\n\\[w(x) =\\simplify[fractionNumbers]{{w}} \\quad [\\var{units_string(qty(1,units[3]))}]\\].
\n$V(x) =\\simplify[fractionNumbers]{{v}}$ $[\\var{units_string(qty(1,units[1]))}]$.
\n$M(x) =\\simplify[fractionNumbers]{{m}}$ $[\\var{units_string(qty(1,units[2]))}]$.
\n{loadBoard}
\n{shearBoard}
\n{momentBoard}
\n", "advice": "Given: The beam is $\\var{qty(L, units[0])}$ long. The loading function is \\[w(x) = \\simplify[fractionNumbers]{{w}}.\\]
\nThe area under the loading function is the downward force on the beam. Here, because positive values of $w$ point down, we replace $w(x)$ with $-w(x)$ to agree with the standard convention that negative forces point down.
\n1. The total load acting on the beam is the integral loading function from $0$ to $L$.
\n\\[\\begin{align}W &= -\\int_0^L w(x)\\; dx \\\\
&= \\int_0^L \\simplify[fractionNumbers]{{-w}}\\; dx\\\\
&= \\left. \\simplify[fractionNumbers]{{polynomial(x,[ 0,0,-h/b, h/(b^2)/3])}}\\;\\right |_0^L \\\\
&= \\var{force(load_integral)}
\\end{align}\\]
By symmetry, the reactions at $x=0$ and $x= L$ are each half this load, pointing up, so:
\n\\[\\begin{align}A &= B=W/2 \\\\
&=\\var{-force(load_integral/2)}\\end{align}\\]
2. The shear function $V(x)$ is the integral of the loading function $w(x)$.
\n\\[\\begin{align} V(x) &= -\\int w(x)\\; dx \\\\
&= \\int \\simplify[fractionNumbers]{{-w}}\\;dx\\\\
&= \\simplify[fractionNumbers]{{polynomial(x,[ 0,0, -h/b, h/(b^2)/3])}} + C_0 \\end{align}\\]
The constant of integration can be found by evaluating the shear function at $x=0$, where $V(0) = A$ to get
\n\\[V(0) = C_0 = \\var{force(-load_integral/2)} \\]
\n5. The moment function is the integral of the shear function
\n\\[\\begin{align} M(x) &= \\int V(x)\\; dx \\\\
&= \\int \\simplify[fractionNumbers]{{polynomial(x,[ 0,0, -h/b, h/(b^2)/3])}} + C_0 \\;dx\\\\
& = \\simplify[fractionNumbers]{{m}} + C_1\\\\
\\end{align}\\]
Since the moment $M(0) = 0$, $C_1 = 0$
\n6. The Maximum shear occurs at the ends, where $dV /dx = -w(x) = 0$
\n\\[\\begin{align}V_{max} &= V(0) = V(L)\\\\
&= \\var{force(maximums[1])}\\end{align}
\\]
7. The Maximum moment occurs at midpoint, $x = \\var{qty(L/2,units[0])}$, where $dM/dx = 0$
\n\\[\\begin{align}M_{max} &= M(\\var{b})\\\\
&= \\var{moment(maximums[2])}\\end{align}\\]
half width of beam \"base\"
", "templateType": "anything", "can_override": false}, "h": {"name": "h", "group": "Ungrouped variables", "definition": "random([1,2,2.5,5,7.5,10])random([10,100])", "description": "distributed load at the center of the beam. The \"height\" of the parabola
", "templateType": "anything", "can_override": false}, "w": {"name": "w", "group": "Ungrouped variables", "definition": "polynomial(x,[0,2 h/b,-h/(b^2)])", "description": "loading function w(x)
", "templateType": "anything", "can_override": false}, "F_A": {"name": "F_A", "group": "Unnamed group", "definition": "rational(2/3 b h)", "description": "Reaction at A = half the downward force ( 2/3 bh)
\nReaction at B is the same.
", "templateType": "anything", "can_override": false}, "v": {"name": "v", "group": "Ungrouped variables", "definition": "polynomial(x,[ F_A,0, -h/b, h/(b^2)/3])", "description": "the shear function. result of integrating -w(x)
", "templateType": "anything", "can_override": false}, "m": {"name": "m", "group": "Ungrouped variables", "definition": "polynomial(x,[0, F_A,0, -h/b/3, h/(b^2)/3/4])", "description": "The moment function m(x), result of integrating v(x)
", "templateType": "anything", "can_override": false}, "w_t": {"name": "w_t", "group": "Unnamed group", "definition": "2 F_A", "description": "Total Weight supported by the beam
", "templateType": "anything", "can_override": false}, "debug": {"name": "debug", "group": "Ungrouped variables", "definition": "false", "description": "", "templateType": "anything", "can_override": false}, "loadBoard": {"name": "loadBoard", "group": "Ungrouped variables", "definition": "let(max, maximums[0],\n jsxgraph(\n 480,200,[-2, 1.2 max, 2 b+2, - max/2],\n merge(\n [ \"$w(x)$\": ['functiongraph', [load_function, 0, L], [name: \"a\", withLabel: true, strokeWidth: 3, strokeColor: \"#CC0000\", fillColor: \"#CC0000\", \n fillOpacity: 0.1,label:[fixed: false, fontSize: 14]]]],\narrows,\n [\"beam\": ['segment', [[0,0],[L,0]], [strokeWidth: 5, color: \"black\"]] ],\n [ \"$A$\": ['segment', [[0,-max 0.4], [0,0]], merge(reactionoptions, [label: [fixed: false, color: \"#CC0000\", fontSize: 16]])]],\n [ \"$B$\": ['segment', [[L,-max 0.4],[L,0],], merge(reactionoptions, [label: [fixed: false, color: \"#CC0000\", fontSize: 16]])]]\n )\n)\n)", "description": "", "templateType": "anything", "can_override": false}, "load_function": {"name": "load_function", "group": "Ungrouped variables", "definition": "expr(polynomials[0])", "description": "", "templateType": "anything", "can_override": false}, "maximums": {"name": "maximums", "group": "Ungrouped variables", "definition": "let(\n w, polynomials[0],\n v, polynomials[1],\n m, polynomials[2],\n [eval(w,b),eval(v,0),eval(m,b)])", "description": "load function at peak
", "templateType": "anything", "can_override": false}, "L": {"name": "L", "group": "Ungrouped variables", "definition": "20", "description": "beamLength
", "templateType": "anything", "can_override": false}, "shear_function": {"name": "shear_function", "group": "Ungrouped variables", "definition": "expr(polynomials[1])", "description": "", "templateType": "anything", "can_override": false}, "moment_function": {"name": "moment_function", "group": "Ungrouped variables", "definition": "expr(polynomials[2])", "description": "", "templateType": "anything", "can_override": false}, "polynomials": {"name": "polynomials", "group": "Ungrouped variables", "definition": "[\npolynomial(x,[0,2 h/b,-h/(b^2)]),\npolynomial(x,[ F_A,0, -h/b, h/(b^2)/3]),\npolynomial(x,[0, F_A,0, -h/b/3, h/(b^2)/3/4])\n]", "description": "", "templateType": "anything", "can_override": false}, "shearBoard": {"name": "shearBoard", "group": "Ungrouped variables", "definition": "let(max, 1.2*maximums[1],\n jsxgraph(\n 480,200,[-2, 1.1 max, 2 b+2, -max],\n [ \n \"$V(x)$\": ['functiongraph', [shear_function, 0, L], [withLabel: true, strokeWidth: 3, strokeColor: \"#CC0000\" ,label:[fixed: false, fontSize: 14]]],\n\n ]\n))", "description": "", "templateType": "anything", "can_override": false}, "momentBoard": {"name": "momentBoard", "group": "Ungrouped variables", "definition": " let(max, maximums[2], color, \"#3070AD\", \n jsxgraph(\n 480,200,[-2, 1.2 max, 2 b+2, -max/3],\n [\"$M(x)$\": ['functiongraph', [moment_function, 0, L], [withLabel: true, strokeWidth: 3, strokeColor: color, label:[fixed: false, fontSize: 14]]],\n ],\n ))", "description": "", "templateType": "anything", "can_override": false}, "shearload": {"name": "shearload", "group": "Ungrouped variables", "definition": "eval(-w,L)", "description": "", "templateType": "anything", "can_override": false}, "force": {"name": "force", "group": "Ungrouped variables", "definition": "f -> siground(qty(f,units[1]),4)", "description": "", "templateType": "anything", "can_override": false}, "moment": {"name": "moment", "group": "Ungrouped variables", "definition": "m -> siground(qty(m,units[2]),4)", "description": "", "templateType": "anything", "can_override": false}, "load_integral": {"name": "load_integral", "group": "Ungrouped variables", "definition": "eval(polynomial(x,[0,0, -h/b, h/(b^2)/3]),L)", "description": "", "templateType": "anything", "can_override": false}, "Arrow": {"name": "Arrow", "group": "Ungrouped variables", "definition": "let( w , polynomials[0],\n (x) -> ['segment', [[x, eval(w,x)],[x,0]],[ fixed: true, color: \"black\",strokewidth: 1.5,highlight: false, lastArrow: [ type: 4 ]]])", "description": "", "templateType": "anything", "can_override": false}, "reactionOptions": {"name": "reactionOptions", "group": "Ungrouped variables", "definition": "[withLabel: true, \"fixed\": true, \"color\": \"#CC0000\", \"strokewidth\": 4, \"highlight\": false, \"lastArrow\": [ \"type\": 4 ] ]", "description": "", "templateType": "anything", "can_override": false}, "Arrows": {"name": "Arrows", "group": "Ungrouped variables", "definition": "dict(map((i)->([(\"A\"+i),Arrow(i)]), 1..L))", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["debug", "L", "b", "h", "w", "v", "m", "maximums", "load_function", "shear_function", "moment_function", "polynomials", "loadBoard", "shearBoard", "momentBoard", "shearload", "force", "moment", "load_integral", "Arrow", "reactionOptions", "Arrows"], "variable_groups": [{"name": "Unnamed group", "variables": ["w_t", "F_A", "units"]}], "functions": {"show_curvesxxx": {"parameters": [["app", "?"]], "type": "anything", "language": "javascript", "definition": "app.promise.then(function(d) {\n d.app.setVisible(\"showV\", true,false);\n d.app.setVisible(\"showM\", true,false);\n d.app.setValue(\"showV\",true);\n d.app.setValue(\"showM\",true);\n});\nreturn \"\"//new Numbas.jme.types.ggbapplet(app);\n"}}, "preamble": {"js": "\n", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": true, "customName": "Load and Reactions", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Determine the total weight supported by the beam and the reactions at $A$ and $B$.
\n$W = $ [[0]]
\n$R_A =$ [[1]]
\n$R_B = $ [[2]]
\n$R_A = R_B =\\simplify[fractionNumbers]{{F_A}}$ = {force(F_A)}
", "stepsPenalty": "10", "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "The total weight is found by integrating the loading function $w(x)$. Positive values indicate a downward load.
\n$\\begin{align}W &= \\simplify{defint(w,x,0,L)}\\\\ &= \\simplify[fractionNumbers,canonicalOrder]{defint({w},x,0,{2b})}\\end{align}$
\nBy symmetry, the reactions are half the weight:
\n$F_A = F_B = \\dfrac{W}{2}$. These point up.
"}], "gaps": [{"type": "engineering-answer", "useCustomName": true, "customName": "$W$", "marks": "10", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "settings": {"correctAnswer": "qty(2 F_A,units[1])", "right": "0.2", "close": "1.0", "C1": "75", "C2": "50", "C3": "25"}}, {"type": "engineering-answer", "useCustomName": true, "customName": "$R_A$", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "settings": {"correctAnswer": "force(F_A)", "right": "0.2", "close": "1.0", "C1": "75", "C2": "50", "C3": "25"}}, {"type": "engineering-answer", "useCustomName": true, "customName": "$R_B$", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "settings": {"correctAnswer": "force(F_A)", "right": "0.2", "close": "1.0", "C1": "75", "C2": "50", "C3": "25"}}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Shear and Bending Moment Functions", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Determine expressions for:
\n$V\\!(x) =$ [[0]]
\n$M\\!(x) =$ [[1]]
\nand then plot the shear and bending moment diagrams.
\n$V(x) = \\simplify[canonicalOrder,fractionNumbers]{{v}}$
\n$M(x) = \\simplify[canonicalOrder,fractionNumbers]{{m}}$
\n", "stepsPenalty": "10", "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {"validate": {"script": "{show_curves(applet)}", "order": "after"}}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "The shear function is found by integrating the loading function. The negative sign is because positive values of w(x) represent a load which points down.
\n$\\begin{align}V(x) &= \\simplify{-defint(w,x,0,x)} \\\\&= \\simplify[fractionNumbers,canonicalOrder]{defint({-w},x,0,L)} \\\\&= \\simplify[fractionNumbers,canonicalOrder]{{v}}\\end{align}$
\nThe bending moment function is found by integrating the shear function.
\n$\\begin{align}M(x) &= \\simplify{defint(V,x,0,x)}\\\\&= \\simplify[fractionNumbers,canonicalOrder]{defint({v},x,0,L)} \\\\&= \\simplify[fractionNumbers,canonicalOrder]{{M}}\\end{align}$
\nIn both cases, the resulting constant of integration is determined by considering the values at $x=0$.
\n$V(0) = F_A, \\text{ and } M(0) = 0$
\n"}], "gaps": [{"type": "jme", "useCustomName": true, "customName": "V(x)", "marks": "10", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "answer": "{expr(v)}", "answerSimplification": "fractionNumbers", "showPreview": true, "checkingType": "sigfig", "checkingAccuracy": "2", "failureRate": 1, "vsetRangePoints": 5, "vsetRange": [0, 1], "checkVariableNames": false, "singleLetterVariables": false, "allowUnknownFunctions": true, "implicitFunctionComposition": false, "caseSensitive": false, "valuegenerators": []}, {"type": "jme", "useCustomName": true, "customName": "M(x)", "marks": "10", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "answer": "{expr(m)}", "answerSimplification": "fractionNumbers", "showPreview": true, "checkingType": "sigfig", "checkingAccuracy": "2", "failureRate": 1, "vsetRangePoints": 5, "vsetRange": [0, 1], "checkVariableNames": false, "singleLetterVariables": false, "allowUnknownFunctions": true, "implicitFunctionComposition": false, "caseSensitive": false, "valuegenerators": []}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Maximum internal loads", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "Give the (signed) values of the largest shear and bending moment occuring anywhere within the beam. Use the standard sign convention for shear and bending moments.
\n$V_{\\text{max}} = $ [[0]] $\\qquad M_{\\text{max}} = $ [[1]]
\n$V_{max} = \\var{siground(qty(eval(v,0),units[1]),4)}$
\n$M_{max} = \\var{siground(qty(eval(m,b),units[0]+\" \" + units[1]),4)}$
\n", "stepsPenalty": "10", "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "The maximum shear occurs at the ends, where $\\simplify{diff(V,x,1)} = -w(x) = 0$ i.e. at $x=0$, or $x=\\var{qty(2b,units[0])}$.
\n$\\begin{align}V_{max} &= V(0) \\\\ &= \\var{siground(qty(F_A,units[1]),4)}\\end{align}$
\nMaximum moment occurs at midpoint, where $\\simplify{diff(M,x,1)} = V = 0$
\n$\\begin{align}M_{max} &= M(\\var{b}) \\\\&= \\var{siground(qty(eval(m,b),units[0] + ' ' + units[1]),4)}\\end{align}$
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