// Numbas version: exam_results_page_options
{"name": "Assignment 4", "metadata": {"description": "<p><strong>MECE3930U: Heat Transfer Assignment 4<br /></strong></p>\n<p><em>Please follow the Numbas guidance first if you did not attend the Numbas&nbsp;session.</em></p>\n<p><em></em></p>\n<p><em></em><strong>This assignment is only to allow a maximum of <span style=\"text-decoration: underline;\">5 attempts</span>.</strong></p>\n<p>Time to complete: unlimited</p>\n<p>All answers should be provided without the units, but attention must be paid to the unit instructions in each question. For example, if your answer is 100.3 W/m2K, type 100.3 only.</p>\n<p></p>\n<p><strong>Important Note: You have to submit your assignment to receive a mark!</strong></p>", "licence": "None specified"}, "duration": 0, "percentPass": 0, "showQuestionGroupNames": false, "showstudentname": true, "question_groups": [{"name": "Group", "pickingStrategy": "all-ordered", "pickQuestions": 1, "questionNames": ["", ""], "questions": [{"name": "A4Q1 v8", "extensions": ["quantities"], "custom_part_types": [{"source": {"pk": 1, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/1/edit"}, "name": "Yes/no", "short_name": "yes-no", "description": "<p>The student is shown two radio choices: \"Yes\" and \"No\". One of them is correct.</p>", "help_url": "", "input_widget": "radios", "input_options": {"correctAnswer": "if(eval(settings[\"correct_answer_expr\"]), 0, 1)", "hint": {"static": true, "value": ""}, "choices": {"static": true, "value": ["Yes", "No"]}}, "can_be_gap": true, "can_be_step": true, "marking_script": "mark:\nif(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)\n\ninterpreted_answer:\nstudentAnswer=0\n\ncorrect_answer:\nif(eval(settings[\"correct_answer_expr\"]),0,1)", "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": "if(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "studentAnswer=0"}, {"name": "correct_answer", "description": "", "definition": "if(eval(settings[\"correct_answer_expr\"]),0,1)"}], "settings": [{"name": "correct_answer_expr", "label": "Is the answer \"Yes\"?", "help_url": "", "hint": "An expression which evaluates to <code>true</code> or <code>false</code>.", "input_type": "mathematical_expression", "default_value": "true", "subvars": false}], "public_availability": "always", "published": true, "extensions": []}], "resources": [["question-resources/1_KUd3zOP.PNG", "/srv/numbas/media/question-resources/1_KUd3zOP.PNG"], ["question-resources/1_RkA5lTG.PNG", "/srv/numbas/media/question-resources/1_RkA5lTG.PNG"], ["question-resources/1_Bpt4XTH.PNG", "/srv/numbas/media/question-resources/1_Bpt4XTH.PNG"], ["question-resources/2_64U8S7t.PNG", "/srv/numbas/media/question-resources/2_64U8S7t.PNG"], ["question-resources/3_y8gDUnF.PNG", "/srv/numbas/media/question-resources/3_y8gDUnF.PNG"], ["question-resources/Capture_zMDQefW.PNG", "/srv/numbas/media/question-resources/Capture_zMDQefW.PNG"], ["question-resources/8_0oM6FF4.png", "/srv/numbas/media/question-resources/8_0oM6FF4.png"], ["question-resources/9_wL67X38.png", "/srv/numbas/media/question-resources/9_wL67X38.png"], ["question-resources/A_pVY1K4N.PNG", "/srv/numbas/media/question-resources/A_pVY1K4N.PNG"], ["question-resources/B_1jmG0Kt.PNG", "/srv/numbas/media/question-resources/B_1jmG0Kt.PNG"], ["question-resources/C_UXadbgx.PNG", "/srv/numbas/media/question-resources/C_UXadbgx.PNG"], ["question-resources/D_f3wxQp4.PNG", "/srv/numbas/media/question-resources/D_f3wxQp4.PNG"], ["question-resources/E.PNG", "/srv/numbas/media/question-resources/E.PNG"], ["question-resources/5.PNG", "/srv/numbas/media/question-resources/5.PNG"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Seama Koohi", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4775/"}], "tags": [], "metadata": {"description": "", "licence": "None specified"}, "statement": "<p>For a laminar flow that undergoes a combined entrance process within a constant surface temperature tube of length <em>L </em>&lt; <em>x</em><sub>fd<em>,t</em></sub> with a flow rate of $\\dot{m}$. Assuming <em>Pr</em> = 3</p>", "advice": "", "rulesets": {}, "variables": {"k": {"name": "k", "group": "Ungrouped variables", "definition": "random(0.12 .. 0.18#0.01)", "description": "", "templateType": "randrange"}, "Di": {"name": "Di", "group": "Ungrouped variables", "definition": "random(0.13 .. 0.15#0.01)", "description": "", "templateType": "randrange"}, "Do": {"name": "Do", "group": "Ungrouped variables", "definition": "random(0.17 .. 0.2#0.01)", "description": "", "templateType": "randrange"}, "ho": {"name": "ho", "group": "Ungrouped variables", "definition": "random(0.17 .. 0.2#0.01)", "description": "", "templateType": "randrange"}, "m": {"name": "m", "group": "Ungrouped variables", "definition": "random(0 .. 1#1)", "description": "", "templateType": "randrange"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["k", "Di", "Do", "ho", "m"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "1_n_2", "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": "<p>What expression can we use to calculate the Nusselt number?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<img src=\"resources/question-resources/A_pVY1K4N.PNG\" width=\"178\" height=\"71\"/>", "<img src=\"resources/question-resources/B_1jmG0Kt.PNG\" width=\"210\" height=\"59\"/>", "<img src=\"resources/question-resources/C_UXadbgx.PNG\" width=\"299\" height=\"105\"/>", "<img src=\"resources/question-resources/D_f3wxQp4.PNG\" width=\"493\" height=\"142\"/>", "<img src=\"resources/question-resources/E.PNG\" width=\"386\" height=\"65\"/>"], "matrix": [0, 0, "0", "5", "0"], "distractors": ["", "", "", "", ""]}, {"type": "m_n_2", "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": "<p>The $Nu$ number that you found is a function of what dimensionless numbers?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": true, "displayType": "checkbox", "displayColumns": 0, "minAnswers": 0, "maxAnswers": 0, "warningType": "none", "showCellAnswerState": true, "markingMethod": "sum ticked cells", "choices": ["$Re$\n<div id=\"gtx-trans\" style=\"position: absolute; left: -74px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "$Ra$", "$Pr$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 8px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "$Gz$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 7px; top: 26px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>"], "matrix": [0, 0, "3", "3"], "distractors": ["", "", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does $Pr$= $ v $<em>&nbsp;</em>/$&alpha;$ vary if the mass flow rate changes?</p>", "settings": {"correct_answer_expr": "false"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does $Pr$= $ v $<em>&nbsp;</em>/$&alpha;$&nbsp;vary if the tube length changes?</p>", "settings": {"correct_answer_expr": "false"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does $Re$ number vary if the mass flow rate changes?</p>", "settings": {"correct_answer_expr": "true"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does <em>Re<sub>D</sub>&nbsp;</em>number vary if the tube length changes?</p>\n<div id=\"gtx-trans\" style=\"position: absolute; left: 62px; top: -6px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "settings": {"correct_answer_expr": "false"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does Gz<em><sub>D</sub>&nbsp;</em>number vary if the mass flow rate changes?</p>\n<div id=\"gtx-trans\" style=\"position: absolute; left: 280px; top: 40px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "settings": {"correct_answer_expr": "false"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Does Gz<em><sub>D</sub>&nbsp;</em>number vary if the tube length changes?</p>", "settings": {"correct_answer_expr": "true"}}, {"type": "1_n_2", "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": "<p>How does Re<sub>D</sub>&nbsp;number vary if the mass flow rate changes from $\\dot{m}$&nbsp;to $\\dot{m}/N$ ?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["does not change\n<div id=\"gtx-trans\" style=\"position: absolute; 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(see the figure below)<img src=\"resources/question-resources/5.PNG\" width=\"406\" height=\"209\"/></p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["does not change\n<div id=\"gtx-trans\" style=\"position: absolute; left: 109px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${N}\\times{Gz_D}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: -130px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${N}^2\\times{Gz_D}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 109px; top: 25.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${Gz_D}\\over{N}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 17px; top: 25.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${Gz_D}\\over{N}^2$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 17px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>"], "matrix": ["3", 0, 0, "0", 0], "distractors": ["", "", "", "", ""]}, {"type": "1_n_2", "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": "<p>How would the $Nu_D$ number vary if the tube is divided into <em>N </em>shorter tubes, each of length <em>L<sub>N</sub> </em>= <em>L</em>/<em>N </em>with a flow rate of $\\dot{m}/N$&nbsp;?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["does not change\n<div id=\"gtx-trans\" style=\"position: absolute; 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left: 109px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${N}\\times{Nu_D}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 90px; top: 25.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${N}^2\\times{Nu_D}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 132px; top: -20px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${Nu_D}\\over{N}$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 41px; top: 25.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "${Nu_D}\\over{N}^2$\n<div id=\"gtx-trans\" style=\"position: absolute; left: 35px; top: 25.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>"], "matrix": ["3", 0, 0, "0", 0], "distractors": ["", "", "", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Can the heat transfer be improved&nbsp;if the tube is divided into&nbsp;<em>N&nbsp;</em>shorter tubes, each of length<em>L<sub>N</sub>&nbsp;</em>=<em>L</em>/<em>N&nbsp;</em>with a flow rate of $\\dot{m}/N$&nbsp;?</p>", "settings": {"correct_answer_expr": "false"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "A4Q2 v5", "extensions": ["quantities"], "custom_part_types": [{"source": {"pk": 1, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/1/edit"}, "name": "Yes/no", "short_name": "yes-no", "description": "<p>The student is shown two radio choices: \"Yes\" and \"No\". One of them is correct.</p>", "help_url": "", "input_widget": "radios", "input_options": {"correctAnswer": "if(eval(settings[\"correct_answer_expr\"]), 0, 1)", "hint": {"static": true, "value": ""}, "choices": {"static": true, "value": ["Yes", "No"]}}, "can_be_gap": true, "can_be_step": true, "marking_script": "mark:\nif(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)\n\ninterpreted_answer:\nstudentAnswer=0\n\ncorrect_answer:\nif(eval(settings[\"correct_answer_expr\"]),0,1)", "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": "if(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "studentAnswer=0"}, {"name": "correct_answer", "description": "", "definition": "if(eval(settings[\"correct_answer_expr\"]),0,1)"}], "settings": [{"name": "correct_answer_expr", "label": "Is the answer \"Yes\"?", "help_url": "", "hint": "An expression which evaluates to <code>true</code> or <code>false</code>.", "input_type": "mathematical_expression", "default_value": "true", "subvars": false}], "public_availability": "always", "published": true, "extensions": []}], "resources": [["question-resources/1_KUd3zOP.PNG", "/srv/numbas/media/question-resources/1_KUd3zOP.PNG"], ["question-resources/1_RkA5lTG.PNG", "/srv/numbas/media/question-resources/1_RkA5lTG.PNG"], ["question-resources/1_Bpt4XTH.PNG", "/srv/numbas/media/question-resources/1_Bpt4XTH.PNG"], ["question-resources/2_64U8S7t.PNG", "/srv/numbas/media/question-resources/2_64U8S7t.PNG"], ["question-resources/3_y8gDUnF.PNG", "/srv/numbas/media/question-resources/3_y8gDUnF.PNG"], ["question-resources/Capture_zMDQefW.PNG", "/srv/numbas/media/question-resources/Capture_zMDQefW.PNG"], ["question-resources/8_0oM6FF4.png", "/srv/numbas/media/question-resources/8_0oM6FF4.png"], ["question-resources/9_wL67X38.png", "/srv/numbas/media/question-resources/9_wL67X38.png"], ["question-resources/A_pVY1K4N.PNG", "/srv/numbas/media/question-resources/A_pVY1K4N.PNG"], ["question-resources/B_1jmG0Kt.PNG", "/srv/numbas/media/question-resources/B_1jmG0Kt.PNG"], ["question-resources/C_UXadbgx.PNG", "/srv/numbas/media/question-resources/C_UXadbgx.PNG"], ["question-resources/D_f3wxQp4.PNG", "/srv/numbas/media/question-resources/D_f3wxQp4.PNG"], ["question-resources/E.PNG", "/srv/numbas/media/question-resources/E.PNG"], ["question-resources/5.PNG", "/srv/numbas/media/question-resources/5.PNG"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Seama Koohi", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4775/"}], "tags": [], "metadata": {"description": "", "licence": "None specified"}, "statement": "<p>To cool a summer home, air is routed through a plastic pipe (<em>k </em>= $\\var{k}$ W/mK, <em>D<sub>i</sub> </em>= $\\var{Di}$ m, <em>D<sub>o</sub> </em>= $\\var{Do}$ m) that is submerged in a body of water. The water temperature is nominally at <em>T</em><sub>&infin;</sub> = 17&deg;C, and a convection coefficient of <em>h<sub>o</sub> </em>= $\\var{ho}$ W/m<sup>2</sup>K is maintained at the outer surface of the pipe. If air from the home enters the pipe at a temperature of <em>T</em><sub>m,i </sub>= 29&deg;C and a mass flow rate of $\\var{m}$ kg/s, what pipe length <em>L</em> is needed to provide a discharge temperature of <em>T</em><sub>m,o</sub> = 21&deg;C?</p>\n<p></p>\n<p><em><strong>Let&rsquo;s work through this assignment in parts:</strong></em></p>", "advice": "", "rulesets": {}, "variables": {"k": {"name": "k", "group": "Ungrouped variables", "definition": "random(0.12 .. 0.18#0.01)", "description": "", "templateType": "randrange"}, "Di": {"name": "Di", "group": "Ungrouped variables", "definition": "random(0.13 .. 0.15#0.01)", "description": "", "templateType": "randrange"}, "Do": {"name": "Do", "group": "Ungrouped variables", "definition": "random(0.17 .. 0.2#0.01)", "description": "", "templateType": "randrange"}, "ho": {"name": "ho", "group": "Ungrouped variables", "definition": "random(1400 .. 1600#10)", "description": "", "templateType": "randrange"}, "m": {"name": "m", "group": "Ungrouped variables", "definition": "random(0.015 .. 0.03#0.001)", "description": "", "templateType": "randrange"}, "Rp": {"name": "Rp", "group": "Ungrouped variables", "definition": "ln(Do/Di)/(2*pi*k)", "description": "", "templateType": "anything"}, "Ro": {"name": "Ro", "group": "Ungrouped variables", "definition": "1/(ho*Pi*Do)", "description": "", "templateType": "anything"}, "Tmi": {"name": "Tmi", "group": "Ungrouped variables", "definition": "29", "description": "", "templateType": "number"}, "Tmo": {"name": "Tmo", "group": "Ungrouped variables", "definition": "21", "description": "", "templateType": "number"}, "Tinf": {"name": "Tinf", "group": "Ungrouped variables", "definition": "17", "description": "", "templateType": "number"}, "Ak": {"name": "Ak", "group": "Ungrouped variables", "definition": "273 + ((Tmi + Tmo) / 2)", "description": "", "templateType": "anything"}, "Re": {"name": "Re", "group": "Ungrouped variables", "definition": "(4*m)/(pi*Di*mu)", "description": "", "templateType": "anything"}, "mu": {"name": "mu", "group": "Ungrouped variables", "definition": "183.6*(10^(-7))", "description": "", "templateType": "anything"}, "Nu": {"name": "Nu", "group": "Ungrouped variables", "definition": "0.023*(Re^(4/5))*(0.707^0.3)", "description": "", "templateType": "anything"}, "hi": {"name": "hi", "group": "Ungrouped variables", "definition": "(0.0261*Nu)/Di", "description": "", "templateType": "anything"}, "u": {"name": "u", "group": "Ungrouped variables", "definition": "1/(((ln(Do/Di))/(2*pi*k))+R1+(1/(ho*pi*Do)))", "description": "", "templateType": "anything"}, "L": {"name": "L", "group": "Ungrouped variables", "definition": "-((ln(1/3))/(u/(m*1007)))", "description": "", "templateType": "anything"}, "R1": {"name": "R1", "group": "Ungrouped variables", "definition": "1/(hi*pi*Di)", "description": "", "templateType": "anything"}, "cc": {"name": "cc", "group": "Ungrouped variables", "definition": "1/(Rp+Ro+R1)", "description": "", "templateType": "anything"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["Tmi", "Tmo", "Tinf", "mu", "k", "Di", "Do", "ho", "m", "Rp", "Ro", "Ak", "Re", "Nu", "hi", "R1", "u", "L", "cc"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "1_n_2", "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": "<p>What mode of heat transfer is present between the air pipe outer surface and water?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Conduction</p>", "Convection", "Radiation"], "matrix": [0, "1", 0], "distractors": ["", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Do we have the convection coefficient between the air pipe outer surface and water?</p>", "settings": {"correct_answer_expr": "true"}}, {"type": "1_n_2", "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": "<p>What mechanism of convection heat transfer is present between the air pipe inner surface and the air?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Free convection</p>", "<p>Forced external flow convection</p>", "Forced internal flow convection"], "matrix": [0, 0, "1"], "distractors": ["", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Do we have the convection coefficient between the air pipe inner surface and the air?</p>\n<div id=\"gtx-trans\" style=\"position: absolute; left: -39px; top: 39.6667px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "settings": {"correct_answer_expr": "false"}}, {"type": "1_n_2", "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": "<p>What mechanism of heat transfer is present between the air pipe outer surface and its inner surface?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Free convection</p>", "<p>Forced external flow convection</p>", "Forced internal flow convection", "Conduction"], "matrix": [0, 0, "0", "1"], "distractors": ["", "", "", ""]}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Do we have a uniform surface temperature or a uniform surface heat flux condition on the inner surface of the pipe?</p>", "settings": {"correct_answer_expr": "false"}}, {"type": "yes-no", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Do we have a uniform surface temperature or a uniform surface heat flux condition on the outer surface of the pipe?</p>\n<div id=\"gtx-trans\" style=\"position: absolute; left: -77px; top: -6px;\">\n<div class=\"gtx-trans-icon\"></div>\n</div>", "settings": {"correct_answer_expr": "false"}}, {"type": "m_n_2", "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": "<p>If we were to use a U value between the air in the pipe and the water outside of it, what would it include? (select all that applies)</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": true, "displayType": "checkbox", "displayColumns": 0, "minAnswers": 0, "maxAnswers": 0, "warningType": "none", "showCellAnswerState": true, "markingMethod": "score per matched cell", "choices": ["R conduction in the pipe", "<p>R conduction in the water</p>", "R convection in the inner surface of the pipe", "R convection in the outer surface of the pipe", "<p>R radiation in the inner surface of the pipe</p>", "<p>R radiation in the outer surface of the pipe</p>"], "matrix": ["1", 0, "1", "1", 0, 0], "distractors": ["", "", "", "", "", ""]}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Calculate the thermal resistance, R&rsquo;, between the air pipe outer surface and its inner surface.</p>", "stepsPenalty": 0, "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": "<p>Hint: You would need pipe conductivity, inner diameter and outer diameter.</p>"}], "minValue": "Rp-0.01", "maxValue": "Rp+0.01", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Calculate the thermal resistance, R&rsquo;, between the air pipe outer surface and water.</p>", "minValue": "Ro-0.0008", "maxValue": "Ro+0.0008", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>We need air flow properties. At what temperature, do we look up values? Provide your answer in K.</p>", "minValue": "297", "maxValue": "299", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the air specific heat that we use in our calculations? (only add the number, but not the unit in J/kg.K)</p>", "minValue": "1006", "maxValue": "1008", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>The air absolute viscosity that we use in our calculations is ???.? x 10<sup>-7</sup> N.s/m<sup>2</sup></p>", "minValue": "182", "maxValue": "185", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the air conductivity that we use in our calculations? (only input the number without unit. In three significant figures, for example as 0.0111, in W/mK)</p>", "minValue": "0.0259", "maxValue": "0.0263", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the air Pr that we use in our calculations? (add the number in three significant figures.)</p>", "minValue": "0.705", "maxValue": "0.709", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Calculate the Reynolds number for the air flow.</p>", "minValue": "Re-100", "maxValue": "Re+100", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "1_n_2", "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": "<p>What type of flow do we have in the pipe?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["laminar", "turbulent"], "matrix": ["0", "2"], "distractors": ["", ""]}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "2", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Assuming a fully developed flow throughout the pipe, what is the Nu number for the air flow?</p>", "minValue": "Nu-0.5", "maxValue": "Nu+0.5", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Calculate the convection coefficient between the air flow and the pipe inner surface.</p>", "minValue": "hi-0.05", "maxValue": "hi+0.05", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Calculate the thermal resistance, R&rsquo;, between the air flow and the pipe inner surface.</p>", "minValue": "R1-0.01", "maxValue": "R1+0.01", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>We know UA<sub>s</sub> = 1 / R and R&rsquo; = R/L. Use this to calculate UA<sub>s</sub>/L and enter it below (provide the number only, with three decimal figures, in W/K):</p>", "minValue": "u-0.05", "maxValue": "u+0.05", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What pipe length <em>L</em> is needed to provide a discharge temperature of <em>T</em><sub>m,o</sub> = 21&deg;C?</p>", "stepsPenalty": 0, "steps": [{"type": "information", "useCustomName": true, "customName": "Hint", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>Hint: Find the relation between UA<sub>s</sub> , the water temperature, the inlet air temperature and the outlet air temperature. Use what you have found in previous parts to find L. (provide the number only, with one digit, in m)</p>"}], "minValue": "L-0.5", "maxValue": "L+0.5", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}]}], "allowPrinting": true, "navigation": {"allowregen": true, "reverse": true, "browse": true, "allowsteps": true, "showfrontpage": true, "showresultspage": "oncompletion", "navigatemode": "sequence", "onleave": {"action": "warnifunattempted", "message": "<p>You did not complete all the questions. Are you sure you want to leave?</p>"}, "preventleave": true, "startpassword": ""}, "timing": {"allowPause": false, "timeout": {"action": "none", "message": "<p>Time is up.</p>"}, "timedwarning": {"action": "none", "message": "<p>5 minutes left!</p>"}}, "feedback": {"showactualmark": true, "showtotalmark": true, "showanswerstate": true, "allowrevealanswer": true, "advicethreshold": 0, "intro": "<p><strong>Instructions:</strong></p>\n<p>Numbas number of attempts: 5 </p>\n<p>Time to complete: unlimited</p>\n<p>All answers should be provided without the units, but attention must be paid to the unit instructions in each question. For example, if your answer is 100.3 W/m2K, type 100.3 only.</p>\n<p>All answers must be rounded to one digit, unless otherwise stated. For example, if your answer is 100.27, type 100.3.</p>", "reviewshowscore": true, "reviewshowfeedback": true, "reviewshowexpectedanswer": true, "reviewshowadvice": true, "feedbackmessages": []}, "contributors": [{"name": "Seama Koohi", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4775/"}], "extensions": ["quantities"], "custom_part_types": [{"source": {"pk": 1, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/1/edit"}, "name": "Yes/no", "short_name": "yes-no", "description": "<p>The student is shown two radio choices: \"Yes\" and \"No\". 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It should award credit and provide feedback based on the student's answer.", "definition": "if(studentanswer=correct_answer,\n  correct(),\n  incorrect()\n)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "studentAnswer=0"}, {"name": "correct_answer", "description": "", "definition": "if(eval(settings[\"correct_answer_expr\"]),0,1)"}], "settings": [{"name": "correct_answer_expr", "label": "Is the answer \"Yes\"?", "help_url": "", "hint": "An expression which evaluates to <code>true</code> or <code>false</code>.", "input_type": "mathematical_expression", "default_value": "true", "subvars": false}], "public_availability": "always", "published": true, "extensions": []}], "resources": [["question-resources/1_KUd3zOP.PNG", "/srv/numbas/media/question-resources/1_KUd3zOP.PNG"], ["question-resources/1_RkA5lTG.PNG", "/srv/numbas/media/question-resources/1_RkA5lTG.PNG"], ["question-resources/1_Bpt4XTH.PNG", "/srv/numbas/media/question-resources/1_Bpt4XTH.PNG"], ["question-resources/2_64U8S7t.PNG", "/srv/numbas/media/question-resources/2_64U8S7t.PNG"], ["question-resources/3_y8gDUnF.PNG", "/srv/numbas/media/question-resources/3_y8gDUnF.PNG"], ["question-resources/Capture_zMDQefW.PNG", "/srv/numbas/media/question-resources/Capture_zMDQefW.PNG"], ["question-resources/8_0oM6FF4.png", "/srv/numbas/media/question-resources/8_0oM6FF4.png"], ["question-resources/9_wL67X38.png", "/srv/numbas/media/question-resources/9_wL67X38.png"], ["question-resources/A_pVY1K4N.PNG", "/srv/numbas/media/question-resources/A_pVY1K4N.PNG"], ["question-resources/B_1jmG0Kt.PNG", "/srv/numbas/media/question-resources/B_1jmG0Kt.PNG"], ["question-resources/C_UXadbgx.PNG", "/srv/numbas/media/question-resources/C_UXadbgx.PNG"], ["question-resources/D_f3wxQp4.PNG", "/srv/numbas/media/question-resources/D_f3wxQp4.PNG"], ["question-resources/E.PNG", "/srv/numbas/media/question-resources/E.PNG"], ["question-resources/5.PNG", "/srv/numbas/media/question-resources/5.PNG"]]}