// Numbas version: exam_results_page_options {"name": "Free Body Diagram 1", "extensions": [], "custom_part_types": [], "resources": [["question-resources/fbd-0_PoiZpWl.png", "/srv/numbas/media/question-resources/fbd-0_PoiZpWl.png"], ["question-resources/fbd-1_xI6ep5I.png", "/srv/numbas/media/question-resources/fbd-1_xI6ep5I.png"], ["question-resources/fbd-2_AdzNdwg.png", "/srv/numbas/media/question-resources/fbd-2_AdzNdwg.png"], ["question-resources/fbd-4_kKlRsW2.png", "/srv/numbas/media/question-resources/fbd-4_kKlRsW2.png"], ["question-resources/fbd-5_zSYquRr.png", "/srv/numbas/media/question-resources/fbd-5_zSYquRr.png"], ["question-resources/fbd-3_frDmR9m.png", "/srv/numbas/media/question-resources/fbd-3_frDmR9m.png"]], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Free Body Diagram 1", "tags": [], "metadata": {"description": "Identify errors in student-drawn free body diagrams of a rigid body.", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "statement": "

Identify the errors (if any) in the student's free body diagram of the smooth bar $ACB$, pinned at $A$.

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{image('resources/question-resources/'+this['filename'])}

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", "advice": "

{mistakes} 

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  1. When isolating the body, don't draw the pin at $C$.
    2. \n
  2. The pin connection at $A$ should be represented by $A_x$ and $A_y$.
    3. \n
  3. The force at $C$ has a known direction, perpendicular to bar $ACB$.  It is best to draw it at that angle rather than breaking it into components
    4. \n
", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"mistakes": {"name": "mistakes", "group": "Ungrouped variables", "definition": "this['errors']", "description": "

the student's mistakes to be found

", "templateType": "anything", "can_override": false}, "choices": {"name": "choices", "group": "Ungrouped variables", "definition": "[\n\"Body incorrectly isolated from supports\",\n\"Missing labels\",\n\"Incorrect labeling\",\n\"Missing arrowheads\",\n\"Incorrect represention at A\",\n\"Incorrect represention at B\",\n\"Incorrect represention at C\",\n\"Extra forces\",\n\"Missing weight\",\n\"Force with known direction shown as components\",\n\"No errors\"\n]\n\n", "description": "

list of possible mistakes -- checkbox labels

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array containing problem image file name and cooresponding errors

", "templateType": "json", "can_override": false}, "this": {"name": "this", "group": "Ungrouped variables", "definition": "fbds[index]", "description": "

the current fbd and mistakes

", "templateType": "anything", "can_override": false}, "index": {"name": "index", "group": "Ungrouped variables", "definition": "random(0..length(fbds)-1)", "description": "

Selects the FBD to show.

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", "templateType": "anything", "can_override": false}, "matrix": {"name": "matrix", "group": "Ungrouped variables", "definition": "map(if(indices(mistakes, d)=[],0,1),d,choices)", "description": "

the marking matrix.  0 if item should not be selected, 1 if it should

", "templateType": "anything", "can_override": true}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["fbds", "this", "mistakes", "choices", "index", "matrix"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": "img{width:600px;}"}, "parts": [{"type": "m_n_2", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": false, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Check {length(mistakes)} {pluralise(length(mistakes),\"box\",\"boxes\")}.

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