// Numbas version: exam_results_page_options
{"name": "Assignment 5", "metadata": {"description": "<p><strong>MECE3930U: Heat Transfer Assignment 5<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": "A5Q1", "extensions": [], "custom_part_types": [], "resources": [["question-resources/Picture1_FaxM44f.png", "/srv/numbas/media/question-resources/Picture1_FaxM44f.png"], ["question-resources/2_hai6MSw.png", "/srv/numbas/media/question-resources/2_hai6MSw.png"], ["question-resources/3_fK805Sv.png", "/srv/numbas/media/question-resources/3_fK805Sv.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>An oven with &nbsp;$\\var{he}$x $1.0$ m x $1.0$ m (height x width x length) size is placed on the ground next to a wall from one side and insulated on this side and its bottom and faces surrounding air from the other three sides and its top surface. The surface of the oven reaches $\\var{Tov}$ K when the outside air and surrounding surfaces are at $300$ K.</p>", "advice": "", "rulesets": {}, "variables": {"He": {"name": "He", "group": "Ungrouped variables", "definition": "random(0.8 .. 1.2#0.05)", "description": "", "templateType": "randrange"}, "Tov": {"name": "Tov", "group": "Ungrouped variables", "definition": "random(450 .. 550#1)", "description": "", "templateType": "randrange"}, "hr": {"name": "hr", "group": "Ungrouped variables", "definition": "5.67*10^(-8)*(Tov^4-300^4)/(Tov-300)", "description": "", "templateType": "anything"}, "q": {"name": "q", "group": "Ungrouped variables", "definition": "(1*1*hr*(Tov-300)+3*He*1*hr*(Tov-300))*0.001", "description": "", "templateType": "anything"}, "g": {"name": "g", "group": "Ungrouped variables", "definition": "He", "description": "", "templateType": "anything"}, "Atop": {"name": "Atop", "group": "Ungrouped variables", "definition": "0.25", "description": "", "templateType": "number"}, "Tfilm": {"name": "Tfilm", "group": "Ungrouped variables", "definition": "(Tov+300)/2", "description": "", "templateType": "anything"}, "Ras": {"name": "Ras", "group": "Ungrouped variables", "definition": "9.81*0.0025*(Tov-300)*He^3/(0.0000383*0.00002641)", "description": "", "templateType": "anything"}, "Nus": {"name": "Nus", "group": "Ungrouped variables", "definition": "(0.825+(0.387*Ras^(1/6))/(1+(0.492/0.69)^(9/16))^(8/27))^2", "description": "", "templateType": "anything"}, "Nut": {"name": "Nut", "group": "Ungrouped variables", "definition": "0.15*Rat^(1/3) ", "description": "", "templateType": "anything"}, "Rat": {"name": "Rat", "group": "Ungrouped variables", "definition": "9.81*0.0025*(Tov-300)*Atop^3/(0.0000383*0.00002641)", "description": "", "templateType": "anything"}, "hs": {"name": "hs", "group": "Ungrouped variables", "definition": "Nus*0.0338/He", "description": "", "templateType": "anything"}, "ht": {"name": "ht", "group": "Ungrouped variables", "definition": "Nut*0.0338/Atop", "description": "", "templateType": "anything"}, "qs": {"name": "qs", "group": "Ungrouped variables", "definition": "hs*He*1*3*(Tov-300)", "description": "", "templateType": "anything"}, "qt": {"name": "qt", "group": "Ungrouped variables", "definition": "ht*(Tov-300)", "description": "", "templateType": "anything"}, "thfr": {"name": "thfr", "group": "Ungrouped variables", "definition": "qs+qt", "description": "", "templateType": "anything"}, "thl": {"name": "thl", "group": "Ungrouped variables", "definition": "q+thfr/1000", "description": "", "templateType": "anything"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["He", "Tov", "hr", "q", "g", "Atop", "Tfilm", "Ras", "Rat", "Nus", "Nut", "hs", "ht", "qs", "qt", "thfr", "thl"], "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 oven surfaces and the surrounding surfaces?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Conduction</p>", "<p>Convection</p>", "Radiation"], "matrix": [0, 0, "1"], "distractors": ["", "", ""]}, {"type": "numberentry", "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>What is the radiation coefficient, <em>h</em><sub>r</sub>, that represents heat transfer between the oven surfaces and the surroundings? You may assume emissivity of the oven surface to be 1. (add the number without units in three significant figures.)</p>", "minValue": "hr-0.5", "maxValue": "hr+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": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the radiation heat flow rate (in kW) from the four surfaces of the oven that are open to the surroundings? (add the number in three significant figures.)</p>", "minValue": "q-0.3", "maxValue": "q+0.3", "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 mode of heat transfer is present between the oven surfaces and air?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Conduction</p>", "<p>Convection</p>", "Radiation"], "matrix": [0, "1", "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>What convection heat transfer mechanism is present between the oven surfaces and air?</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: think about the air movement around the oven; is it forced or due to buoyancy forces?</p>"}], "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>External forced convection</p>", "<p>External free convection</p>", "<p>Internal forced convection</p>", "<p>Internal free convection</p>"], "matrix": [0, "1", "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>What dimensionless number do we use to know whether the air film flow on the surfaces are laminar or turbulent?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Re", "Ra", "Nu", "Pr"], "matrix": [0, "1", 0, 0], "distractors": ["", "", "", ""]}, {"type": "numberentry", "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>What is the characteristic length (in meters) that we use in calculation of Ra for the side walls? (add the number in three significant figures.)</p>", "minValue": "g-0.1", "maxValue": "g+0.1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the characteristic length (in meters) that we use in calculation of Ra for the top wall? (add the number in two significant figures.)</p>", "minValue": "Atop-0.01", "maxValue": "Atop+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": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the film temperature (in Kelvins) that we use in using the properties in calculation of Ra?</p>", "minValue": "Tfilm-1", "maxValue": "Tfilm+1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>Assuming the following properties for the air film:</p>\n<p><img src=\"resources/question-resources/Picture1_FaxM44f.png\" alt=\"\"/></p>\n<p>What is Ra for the side walls?</p>", "minValue": "Ras-4000000", "maxValue": "Ras+4000000", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>Assuming the following properties for the air film:</p>\n<p><img src=\"resources/question-resources/Picture1_FaxM44f.png\" alt=\"\"/></p>\n<p>What is Ra for the top wall?</p>\n<p></p>", "minValue": "Rat-40000", "maxValue": "Rat+40000", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the Nu for the side walls? (add the number in three significant figures.)</p>", "minValue": "Nus-3", "maxValue": "Nus+3", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the Nu for the top wall? (add the number in three significant figures.)</p>", "minValue": "Nut-0.8", "maxValue": "Nut+0.8", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the convection coefficient, <em>h</em>, for the side walls? (add the number in two significant figures.)</p>", "minValue": "hs-0.1", "maxValue": "hs+0.1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the convection coefficient, <em>h</em>, for the top wall? (add the number in two significant figures.)</p>", "minValue": "ht-0.3", "maxValue": "ht+0.3", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the heat flow rate (in Watts) via convection for the side walls?</p>", "minValue": "qs-50", "maxValue": "qs+50", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the heat flow rate (in Watts) via convection for the top wall?</p>", "minValue": "qt-8", "maxValue": "qt+8", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the total heat flow rate (in Watts) via convection?</p>", "minValue": "thfr-40", "maxValue": "thfr+40", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the total heat loss (in kW) from the oven to the air and the surrounding surfaces?</p>", "minValue": "thl-1", "maxValue": "thl+1", "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>If the temperature of the oven was higher, heat loss would increase more due to which heat transfer mode?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Radiation", "<p>Convection</p>", "<p>Cannot comment</p>"], "matrix": ["1", 0, 0], "distractors": ["", "", ""]}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "A5Q2", "extensions": [], "custom_part_types": [], "resources": [], "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>A long steel bar ($\\var{d}$ mm diameter) at 455&deg;C is placed horizontally in a water bath at 100&deg;C under atmospheric pressure.</p>", "advice": "", "rulesets": {}, "variables": {"d": {"name": "d", "group": "Ungrouped variables", "definition": "random(15 .. 25#1)", "description": "", "templateType": "randrange"}, "em": {"name": "em", "group": "Ungrouped variables", "definition": "random(0.8 .. 1#0.05)", "description": "", "templateType": "randrange"}, "hconv": {"name": "hconv", "group": "Ungrouped variables", "definition": "0.0379*0.62/(d/1000)*(9.8*(957.9-0.4005)*2824*1000*((d/1000)^3)/(0.00004704*0.0379*355))^0.25 ", "description": "", "templateType": "anything"}, "hrad": {"name": "hrad", "group": "Ungrouped variables", "definition": "em*0.0000000567*((455+273)^4-(100+273)^4)/(455-100) ", "description": "", "templateType": "anything"}, "hov": {"name": "hov", "group": "Ungrouped variables", "definition": "hconv+0.75*hrad", "description": "", "templateType": "anything"}, "q": {"name": "q", "group": "Ungrouped variables", "definition": "hov*pi*d/1000*(455-100) ", "description": "", "templateType": "anything"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["d", "em", "hconv", "hrad", "hov", "q"], "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>With no means to keep the bar at its initial temperature, how is the temperature of the bar going to change?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Decreases", "Increases", "<p>Cannot comment</p>"], "matrix": ["1", 0, 0], "distractors": ["", "", ""]}, {"type": "numberentry", "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>What is the initial temperature difference between the bar and the water?</p>", "minValue": "354.8", "maxValue": "355.2", "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>If heat is transferred from the bar to the water, What would happen to the water?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["<p>Its temperature will increase.</p>", "<p>Its temperature will decrease.</p>", "It will boil.", "<p>It will condense.</p>", "<p>Cannot comment with the current information.</p>"], "matrix": [0, 0, "1", 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>What type of heat transfer mechanism is present when the bar is initially placed in water?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Film boiling", "<p>Nucleate boiling</p>"], "matrix": ["1", 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>What mode(s) of heat transfer are initially present between the surface of the bar and the water when the bar is initially placed in water?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "checkbox", "displayColumns": 0, "minAnswers": 0, "maxAnswers": 0, "warningType": "none", "showCellAnswerState": true, "markingMethod": "sum ticked cells", "choices": ["<p>Conduction</p>", "Convection", "Radiation"], "matrix": [0, "0.5", "0.5"], "distractors": ["", "", ""]}, {"type": "numberentry", "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>Using the textbook tables, what temperature (in Kelvins) do we use in order to read water vapor information when the bar is initially placed in water?</p>", "minValue": "548", "maxValue": "552", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the water vapor density (in kg/m<sup>3</sup>), as read from the tables? (Enter the value in four significant digits)</p>", "minValue": "0.4001", "maxValue": "0.4006", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the water vapor specific heat (in J/kg.K), as read from the tables? (Enter the value in four significant digits)</p>", "minValue": "1995", "maxValue": "1999", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the water vapor kinematic viscosity (in m<sup>2</sup>/s), as read from the tables? (Enter the value in four significant digits)</p>", "minValue": "0.00004701", "maxValue": "0.00004707", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the water vapor conductivity (in W/mK), as read from the tables? (Enter the value in three significant digits)</p>", "minValue": "0.0378", "maxValue": "0.0380", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What temperature (in Celcius) do we use in order to read saturated water information from the textbook tables?</p>", "minValue": "99", "maxValue": "101", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the saturated water density (in kg/m<sup>3</sup>)? (Enter the value in four significant digits)</p>", "minValue": "957.7", "maxValue": "958.1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the heat of vaporization of water, <em>h<sub>fg</sub></em> (in kJ/kg), as read from the tables? (Enter the value in four significant digits)</p>", "minValue": "2255", "maxValue": "2259", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the corrected heat of vaporization of water, <em>h<sub>fg</sub></em> (in kJ/kg), when used in boiling Nu number calculations? (Enter the value in four significant digits)</p>", "minValue": "2822", "maxValue": "2826", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the convection coefficient (in W/m<sup>2</sup>K) for convection between the surface of the bar and the water (excluding radiation effects) when the bar is initially placed in water? (Enter the value in three significant digits)</p>", "minValue": "hconv-1", "maxValue": "hconv+1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the radiation coefficient, <em>h</em><sub>r</sub>, (in W/m<sup>2</sup>K) for radiation between the surface of the bar and the water when the bar is initially placed in water? You may assume emissivity of the steel bar to be $\\var{em}$ . (Enter the value in three significant digits)</p>", "minValue": "hrad-4", "maxValue": "hrad+4", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>What is the overall convection coefficient in (W/m<sup>2</sup>K) accounting for the effects of both convection and radiation between the surface of the bar and the water when the bar is initially placed in water? Enter the value in three significant digits)</p>", "minValue": "hov-3", "maxValue": "hov+3", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>Estimate the initial heat transfer rate per unit length of the bar to the water (in W/m) when it is initially placed in water.</p>", "minValue": "q-50", "maxValue": "q+50", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "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>If we never run short of water in the water bath, what would be the temperature of the bar eventually (in C) when steady state has reached?</p>", "minValue": "99", "maxValue": "101", "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 heat transfer mechanism is present when the bar has cooled to 110&deg;C?</p>", "minMarks": 0, "maxMarks": 0, "shuffleChoices": false, "displayType": "radiogroup", "displayColumns": 0, "showCellAnswerState": true, "choices": ["Film boiling", "Nucleate boiling"], "matrix": [0, "1"], "distractors": ["", ""]}], "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>If applicable, please use four significant figures.</p>\n<p></p>\n<p><strong>Important Note: You have to submit your assignment to receive a mark!</strong></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": [], "custom_part_types": [], "resources": [["question-resources/Picture1_FaxM44f.png", "/srv/numbas/media/question-resources/Picture1_FaxM44f.png"], ["question-resources/2_hai6MSw.png", "/srv/numbas/media/question-resources/2_hai6MSw.png"], ["question-resources/3_fK805Sv.png", "/srv/numbas/media/question-resources/3_fK805Sv.png"]]}