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55 lines
2.2 KiB
HTML
55 lines
2.2 KiB
HTML
<div class="book-prose">
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<p>
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In HKDSE Physics, force and motion are linked by three core ideas:
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<span class="physics-key-term">inertia</span>,
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<span class="physics-key-term">net force</span>, and
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<span class="physics-key-term">acceleration</span>. This chapter gives you one practical flow:
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draw forces, find the net force, then predict acceleration with Newton's second law.
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</p>
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<h2 id="newtons-laws" class="book-prose__heading">Newton's three laws</h2>
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<ol>
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<li>
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<strong>First law:</strong> if net force is zero, velocity stays constant (including rest).
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</li>
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<li>
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<strong>Second law:</strong> acceleration is proportional to net force and inversely proportional
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to mass.
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</li>
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<li>
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<strong>Third law:</strong> forces come in equal and opposite interaction pairs.
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</li>
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</ol>
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<div class="book-callout book-callout--formula" role="note">
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<p class="book-callout__label">Core equation</p>
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<p class="book-formula">\[ \vec{F}_{\text{net}} = m\vec{a} \]</p>
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</div>
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<h2 id="workflow" class="book-prose__heading">Problem-solving workflow</h2>
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<ol>
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<li>Choose one object as your system.</li>
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<li>Sketch all external forces in a free-body diagram.</li>
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<li>Resolve forces by direction and compute net force.</li>
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<li>Use \(a = F_{\text{net}} / m\), then connect to motion equations.</li>
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</ol>
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<h2 id="interactive-force-lab" class="book-prose__heading">Interactive force lab</h2>
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<p>
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Adjust mass, pulling force, and surface friction. The demo computes friction, net force,
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acceleration, and the motion state for a 3-second interval from rest.
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</p>
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</div>
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<div class="physics-widget-mount" data-widget="force-lab" data-pagefind-ignore></div>
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<div class="book-prose">
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<h2 id="interactive-motion-lab" class="book-prose__heading">Interactive motion graphs</h2>
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<p>
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Change initial velocity, acceleration, and elapsed time to inspect
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<span class="physics-key-term">v-t</span> and <span class="physics-key-term">s-t</span> behavior.
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This connects Newton's second law to kinematics directly.
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</p>
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</div>
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<div class="physics-widget-mount" data-widget="motion-lab" data-pagefind-ignore></div>
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