// Numbas version: finer_feedback_settings {"name": "Maria's copy of Rate of change", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"rulesets": {}, "variables": {"b": {"name": "b", "description": "", "templateType": "randrange", "group": "Ungrouped variables", "definition": "random(3..10#1)"}, "a": {"name": "a", "description": "", "templateType": "randrange", "group": "Ungrouped variables", "definition": "random(100..300#5)"}}, "name": "Maria's copy of Rate of change", "variablesTest": {"maxRuns": 100, "condition": ""}, "functions": {}, "ungrouped_variables": ["a", "b"], "tags": [], "metadata": {"description": "

Rate of change problem involving velocity & acceleration

", "licence": "Creative Commons Attribution 4.0 International"}, "extensions": [], "parts": [{"type": "gapfill", "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "marks": 0, "gaps": [{"minValue": "{a}-9.8*{b}", "allowFractions": false, "precisionPartialCredit": 0, "marks": 1, "scripts": {}, "strictPrecision": false, "precisionMessage": "You have not given your answer to the correct precision.", "type": "numberentry", "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "precisionType": "dp", "showPrecisionHint": false, "maxValue": "{a}-9.8*{b}", "correctAnswerFraction": false, "variableReplacements": [], "precision": "1"}, {"minValue": "{a}^2/19.6", "allowFractions": false, "precisionPartialCredit": 0, "marks": 1, "scripts": {}, "strictPrecision": false, "precisionMessage": "You have not given your answer to the correct precision.", "type": "numberentry", "variableReplacementStrategy": "originalfirst", "showCorrectAnswer": true, "precisionType": "dp", "showPrecisionHint": false, "maxValue": "{a}^2/19.6", "correctAnswerFraction": false, "variableReplacements": [], "precision": "1"}], "scripts": {}, "variableReplacements": [], "prompt": "

Calculate the speed of the missile (m/s) \\(\\var{b}\\) seconds after launch. Give your answer correct to one decimal place.

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\\(v = \\) [[0]]m/s

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What is the maximum height achieved by this missile? Give your answer correct to one decimal place.

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\\(h = \\) [[1]]m

"}], "advice": "

\\(h=\\var{a}t-4.9t^2\\)

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Recall that speed is the rate of change of position with respect to time   i.e. \\(v=\\frac{dh}{dt}\\)

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\\(v=\\frac{dh}{dt}=\\var{a}-2*4.9t\\)

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when \\(t=\\var{b}\\)

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\\(v=\\var{a}-2*4.9*\\var{b}\\)

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\\(v=\\simplify{{a}-9.8*{b}}m/s\\)

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The missile will reach its maximum height when its speed = 0.   i.e. \\(v=\\frac{dh}{dt}=\\var{a}-2*4.9t=0\\)

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\\(\\var{a}=9.8t\\)

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\\(t=\\var{a}/9.8\\)

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The maximum height reached will occur when \\(t=\\simplify{{a}/9.8}\\)

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\\(h=\\var{a}*\\left(\\simplify{{a}/9.8}\\right)-4.9*\\left(\\simplify{{a}/9.8}\\right)^2\\)

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\\(h=\\simplify{{a}^2/19.6}\\)

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\\(h=\\simplify{{{a}/{19.6}^0.5}^2}\\)

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", "variable_groups": [], "statement": "

A missile is launched straight up in the air. The height of the missile, \\(h\\) metres, above the ground \\(t\\) seconds after the launch button is pressed is given by:

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\\(h=\\var{a}t-4.9t^2\\)

", "preamble": {"css": "", "js": ""}, "type": "question", "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}, {"name": "Maria Aneiros", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/3388/"}]}]}], "contributors": [{"name": "Frank Doheny", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/789/"}, {"name": "Maria Aneiros", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/3388/"}]}