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[
{
"slide": 1,
"fragments": [
{
"fragment_index": -1,
"text_description": "Why cars skid?\nUncover the invisible grip between tyres and the road.",
"image_description": ""
}
]
},
{
"slide": 2,
"fragments": [
{
"fragment_index": -1,
"text_description": "Multiple Choice Question\nCorrect!\nYes, μ drops on wet roads.\nIncorrect\nNot quite. The weight is unchanged; grip depends on μ.\nconst correctOption = 1;\n const answerCards = document.querySelectorAll('.answer-card');\n const submitBtn = document.getElementById('submitBtn');\n const feedbackCorrect = document.getElementById('feedbackCorrect');\n const feedbackIncorrect = document.getElementById('feedbackIncorrect');\n \n let selectedOption = null;\n \n answerCards.forEach((card, index) => {\n card.addEventListener('click', () => {\n answerCards.forEach(c => c.classList.remove('border-blue-500', 'bg-blue-50'));\n card.classList.add('border-blue-500', 'bg-blue-50');\n selectedOption = index;\n });\n });\n \n submitBtn.addEventListener('click', () => {\n if (selectedOption === null) return;\n \n if (selectedOption === correctOption) {\n feedbackCorrect.classList.remove('hidden');\n feedbackIncorrect.classList.add('hidden');\n } else {\n feedbackIncorrect.classList.remove('hidden');\n feedbackCorrect.classList.add('hidden');\n }\n });",
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},
{
"fragment_index": 1,
"text_description": "Question\nA wet surface primarily lowers the",
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},
{
"fragment_index": 2,
"text_description": "1\nnormal force on tyres",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "2\ncoefficient of friction",
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},
{
"fragment_index": 4,
"text_description": "3\nmass of the car",
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},
{
"fragment_index": 5,
"text_description": "4\nair resistance",
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},
{
"fragment_index": 6,
"text_description": "Hint:\nThink about how slippery ice feels.",
"image_description": ""
},
{
"fragment_index": 7,
"text_description": "Submit Answer",
"image_description": ""
}
]
},
{
"slide": 3,
"fragments": [
{
"fragment_index": -1,
"text_description": "Why slippage?",
"image_description": ""
},
{
"fragment_index": 1,
"text_description": "Friction",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "Friction is a surface force that resists motion because countless microscopic bumps on the two surfaces lock together.\nA thin film of water acts like tiny ball bearings, loosening the lock-up and lowering friction, so wet floors feel slippery.",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "Source: Engineering Tribology texts",
"image_description": ""
}
]
},
{
"slide": 4,
"fragments": [
{
"fragment_index": 1,
"text_description": "Static friction",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "Term\nStatic friction\nDefinition\nContact force that keeps a body at rest by adjusting to oppose impending motion, along the surface and opposite the applied push.",
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},
{
"fragment_index": 3,
"text_description": "Maximum value\n\\(f_{s,\\text{max}} = \\mu_s N\\)\nBeyond this limit the object begins to move.",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "Self-adjusting\nOpposes impending motion\nAlong surface",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "",
"image_description": "https://asset.sparkl.ac/pb/sparkl-vector-images/img_ncert/PHkJpNmR6gI236OSJaoIOqiwyvAb6FtwLeyAzMrj.png"
}
]
},
{
"slide": 5,
"fragments": [
{
"fragment_index": -1,
"text_description": "Static vs Kinetic",
"image_description": ""
},
{
"fragment_index": 1,
"text_description": "Static Friction\nSelf-adjusts up to a limiting value.\nMaximum \\(F_{\\text{max}} = \\mu_s N\\).\nUsually larger than kinetic friction.",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "Kinetic Friction\nActs once surfaces slide.\nNearly constant: \\(F_k = \\mu_k N\\).\n\\(\\mu_k\\) is smaller than \\(\\mu_s\\).",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "Key Similarities\nBoth oppose relative motion between surfaces.\nDirection is along contact and opposite to slide.",
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}
]
},
{
"slide": 6,
"fragments": [
{
"fragment_index": -1,
"text_description": "Key equations",
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},
{
"fragment_index": 1,
"text_description": "\\[f_{s,\\text{max}}=\\mu_s N \\qquad f_k=\\mu_k N\\]\nBoth forces are proportional to the normal reaction \\(N\\).",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "Variable Definitions\n\\(f_{s,\\text{max}}\\)\nmaximum static friction\n\\(f_k\\)\nkinetic friction\n\\(\\mu_s\\)\ncoefficient of static friction\n\\(\\mu_k\\)\ncoefficient of kinetic friction\n\\(N\\)\nnormal reaction force",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "Applications\nSource: NCERT Section 5.4",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "Predict slip onset\nCompare applied force with \\(f_{s,\\text{max}}\\) to decide if motion starts.",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "Calculate sliding force\nUse \\(f_k\\) to find the net force once the object is moving.",
"image_description": ""
}
]
},
{
"slide": 7,
"fragments": [
{
"fragment_index": 1,
"text_description": "Force vs Friction Graph\nInterpret how friction responds as applied force increases.",
"image_description": ""
},
{
"fragment_index": -1,
"text_description": "Friction first rises with force (\\(F_s\\)), then drops to a flat kinetic level (\\(F_k\\)).",
"image_description": "https://asset.sparkl.ac/pb/sparkl-vector-images/img_ncert/XpXRy1THzVtUNEX4YDJ7vYsQp6b72Q5lPqSg5VGF.png"
},
{
"fragment_index": 2,
"text_description": "Key observation\nNotice the sudden drop at motion onset.",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "Static region: \\(F_f = F_{applied}\\) up to \\(F_s^{\\max}= \\mu_s N\\).\nCorner point marks the instant the block starts to move.\nKinetic region: friction holds nearly constant at \\(F_k = \\mu_k N\\).",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "Tip: Because \\(F_s^{\\max} > F_k\\), the graph always drops from \\(F_s\\) to \\(F_k\\) when sliding begins.",
"image_description": ""
}
]
},
{
"slide": 8,
"fragments": [
{
"fragment_index": 1,
"text_description": "Worked Example\nCalculate friction on a 5 kg block pushed 15 N on a horizontal surface.",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "1\nList data\n\\(m = 5\\text{ kg},\\; \\mu_s = 0.4,\\; \\mu_k = 0.3,\\; F_{\\text{app}} = 15\\text{ N}\\).",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "2\nFind normal \\(N\\)\nHorizontal plane ⇒ \\(N = mg = 5 \\times 9.8 = 49\\text{ N}\\).",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "3\nStatic limit\n\\(f_{s,\\max} = \\mu_s N = 0.4 \\times 49 = 19.6\\text{ N}\\).",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "4\nCompare & decide\n15 N < 19.6 N ⇒ block remains at rest; \\(f_s = 15\\text{ N}\\) (use \\(f_s\\), not \\(f_k\\)).",
"image_description": ""
}
]
},
{
"slide": 9,
"fragments": [
{
"fragment_index": -1,
"text_description": "Common pitfalls",
"image_description": ""
},
{
"fragment_index": 1,
"text_description": "Main Points\n1\nFriction resists relative motion, not the applied push.\n2\nChanging contact area rarely changes the coefficient \\( \\mu \\).\n3\nUsually \\( \\mu_k < \\mu_s \\); force drops once sliding starts.",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "Key Highlights\nSet friction arrow along intended slide, not along applied force.\nGrip depends on normal force, so footprint size cancels out.\nExpect a step down in required force once motion begins.",
"image_description": ""
}
]
},
{
"slide": 10,
"fragments": []
},
{
"slide": 11,
"fragments": [
{
"fragment_index": -1,
"text_description": "Multiple Choice Question\nCorrect!\nWell done—0.98 N opposes motion.\nIncorrect\nRecalculate \\(N = mg\\) first.\nconst correctOption = 1;\n const answerCards = document.querySelectorAll('.answer-card');\n const submitBtn = document.getElementById('submitBtn');\n const feedbackCorrect = document.getElementById('feedbackCorrect');\n const feedbackIncorrect = document.getElementById('feedbackIncorrect');\n \n let selectedOption = null;\n \n answerCards.forEach((card, index) => {\n card.addEventListener('click', () => {\n answerCards.forEach(c => c.classList.remove('border-blue-500', 'bg-blue-50'));\n card.classList.add('border-blue-500', 'bg-blue-50');\n selectedOption = index;\n });\n });\n \n submitBtn.addEventListener('click', () => {\n if (selectedOption === null) return;\n \n if (selectedOption === correctOption) {\n feedbackCorrect.classList.remove('hidden');\n feedbackIncorrect.classList.add('hidden');\n } else {\n feedbackIncorrect.classList.remove('hidden');\n feedbackCorrect.classList.add('hidden');\n }\n });",
"image_description": ""
},
{
"fragment_index": 1,
"text_description": "Question\nTransfer check: A 2 kg puck slides on ice (μ\nk\n= 0.05). Take g = 9.8 m/s². Select the kinetic friction force acting on the puck.",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "1\n0.49 N",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "2\n0.98 N",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "3\n1.96 N",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "4\n4.9 N",
"image_description": ""
},
{
"fragment_index": 6,
"text_description": "Hint:\nUse \\(f = \\mu_k N\\); here \\(N\\) equals the weight.",
"image_description": ""
},
{
"fragment_index": 7,
"text_description": "Submit Answer",
"image_description": ""
}
]
},
{
"slide": 12,
"fragments": [
{
"fragment_index": 1,
"text_description": "Key takeaways\nFour friction facts to remember.",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "1\nStatic vs kinetic\nStatic blocks start; kinetic opposes sliding.",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "2\nProportional to \\(N\\)\nMore normal force → more friction.",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "3\nMaterial, not area\n\\( \\mu \\) is set by surface pair, area irrelevant.",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "4\nAngle of repose\nMeasure \\( \\mu_s \\) using \\( \\tan\\theta = \\mu_s \\).",
"image_description": ""
}
]
},
{
"slide": 13,
"fragments": [
{
"fragment_index": -1,
"text_description": "Multiple Choice Question\nCorrect!\nYes—higher \\( \\mu_s \\) raises the limit.\nIncorrect\nArea and \\( N \\) alone don't raise the limit unless \\( \\mu \\) changes.\n// MCQ interaction logic\n const correctOption = 2;\n const answerCards = document.querySelectorAll('.answer-card');\n const submitBtn = document.getElementById('submitBtn');\n const feedbackCorrect = document.getElementById('feedbackCorrect');\n const feedbackIncorrect = document.getElementById('feedbackIncorrect');\n \n let selectedOption = null;\n \n answerCards.forEach((card, index) => {\n card.addEventListener('click', () => {\n answerCards.forEach(c => c.classList.remove('border-blue-500', 'bg-blue-50'));\n card.classList.add('border-blue-500', 'bg-blue-50');\n selectedOption = index;\n });\n });\n \n submitBtn.addEventListener('click', () => {\n if (selectedOption === null) return;\n \n if (selectedOption === correctOption) {\n feedbackCorrect.classList.remove('hidden');\n feedbackIncorrect.classList.add('hidden');\n } else {\n feedbackIncorrect.classList.remove('hidden');\n feedbackCorrect.classList.add('hidden');\n }\n });",
"image_description": ""
},
{
"fragment_index": 1,
"text_description": "Question\nWhich change increases the static friction limit?",
"image_description": ""
},
{
"fragment_index": 2,
"text_description": "1\nReduce surface roughness",
"image_description": ""
},
{
"fragment_index": 3,
"text_description": "2\nDecrease normal force",
"image_description": ""
},
{
"fragment_index": 4,
"text_description": "3\nUse stickier materials",
"image_description": ""
},
{
"fragment_index": 5,
"text_description": "4\nIncrease contact area",
"image_description": ""
},
{
"fragment_index": 6,
"text_description": "Hint:\nThink \\( \\mu_s \\).",
"image_description": ""
},
{
"fragment_index": 7,
"text_description": "Submit Answer",
"image_description": ""
}
]
}
]