<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e293b;
      background: transparent;
      padding: 6px;
      height: 100%;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
      width: 100%;
      max-width: 650px;
      margin: 0 auto;
    }

    .panel {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
    }

    .panel.true-pair {
      border-color: #86efac;
      background: linear-gradient(180deg, #f0fdf4 0%, #ffffff 40%);
    }

    .panel.non-pair {
      border-color: #fca5a5;
      background: linear-gradient(180deg, #fef2f2 0%, #ffffff 40%);
    }

    .title {
      font-size: 13px;
      font-weight: 700;
      margin-bottom: 6px;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .true-pair .title { color: #166534; }
    .non-pair .title { color: #991b1b; }

    .diagram-box {
      width: 100%;
      height: 140px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .tag-list {
      display: flex;
      flex-direction: column;
      gap: 4px;
      width: 100%;
      margin-top: 6px;
    }

    .tag {
      font-size: 11px;
      font-weight: 600;
      padding: 4px 6px;
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
    }

    .tag.ok {
      background: #dcfce7;
      color: #15803d;
    }

    .tag.bad {
      background: #fee2e2;
      color: #b91c1c;
    }

    @media (min-width: 480px) {
      .title { font-size: 15px; }
      .diagram-box { height: 160px; }
      .tag { font-size: 12px; padding: 5px 8px; }
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="panel true-pair">
      <div class="title">✓ Third Law Pair</div>
      <div class="diagram-box">
        <svg viewBox="0 0 200 150" xmlns="http://www.w3.org/2000/svg">
          <defs>
            <marker id="arr-green" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
              <polygon points="0 0, 6 3, 0 6" fill="#16a34a" />
            </marker>
          </defs>

          
          <circle cx="45" cy="45" r="14" fill="#94a3b8" />
          <text x="45" y="24" text-anchor="middle" font-size="11" font-weight="bold" fill="#475569">Moon</text>

          
          <circle cx="155" cy="105" r="22" fill="#3b82f6" />
          <text x="155" y="142" text-anchor="middle" font-size="11" font-weight="bold" fill="#1d4ed8">Earth</text>

          
          <line x1="45" y1="45" x2="88" y2="68" stroke="#16a34a" stroke-width="2.5" marker-end="url(#arr-green)" />
          <text x="50" y="80" font-size="9.5" font-weight="700" fill="#15803d">Gravity</text>

          
          <line x1="155" y1="105" x2="112" y2="82" stroke="#16a34a" stroke-width="2.5" marker-end="url(#arr-green)" />
          <text x="150" y="78" text-anchor="end" font-size="9.5" font-weight="700" fill="#15803d">Gravity</text>
        </svg>
      </div>
      <div class="tag-list">
        <div class="tag ok">✓ 2 Different Objects</div>
        <div class="tag ok">✓ Same Force Type</div>
      </div>
    </div>

    
    <div class="panel non-pair">
      <div class="title">✗ Not a Pair</div>
      <div class="diagram-box">
        <svg viewBox="0 0 200 150" xmlns="http://www.w3.org/2000/svg">
          <defs>
            <marker id="arr-blue" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
              <polygon points="0 0, 6 3, 0 6" fill="#2563eb" />
            </marker>
            <marker id="arr-red" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
              <polygon points="0 0, 6 3, 0 6" fill="#dc2626" />
            </marker>
          </defs>

          
          <rect x="35" y="85" width="130" height="8" rx="2" fill="#cbd5e1" />
          <line x1="55" y1="93" x2="55" y2="135" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <line x1="145" y1="93" x2="145" y2="135" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <text x="100" y="130" text-anchor="middle" font-size="10" font-weight="bold" fill="#64748b">Table</text>

          
          <rect x="65" y="60" width="70" height="25" rx="3" fill="#f59e0b" />
          <text x="100" y="76" text-anchor="middle" font-size="11" font-weight="bold" fill="#ffffff">Book</text>

          
          <line x1="100" y1="72" x2="100" y2="24" stroke="#2563eb" stroke-width="2.5" marker-end="url(#arr-blue)" />
          <text x="108" y="34" font-size="9.5" font-weight="700" fill="#2563eb">Normal</text>

          
          <line x1="100" y1="72" x2="100" y2="120" stroke="#dc2626" stroke-width="2.5" marker-end="url(#arr-red)" />
          <text x="108" y="112" font-size="9.5" font-weight="700" fill="#dc2626">Gravity</text>
        </svg>
      </div>
      <div class="tag-list">
        <div class="tag bad">✗ Same Object (Book)</div>
        <div class="tag bad">✗ Different Force Types</div>
      </div>
    </div>
  </div>

</body>
</html>

Interaction Pairs and Newton's Third Law

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Newton's Second & Third Law: Cannon & Cannonball</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #0f172a;
      width: 100%;
      min-height: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 12px 10px;
      user-select: none;
    }

    .main-wrapper {
      width: 100%;
      max-width: 600px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    /* Interactive SVG Scene */
    .scene-svg-wrapper {
      width: 100%;
      border-radius: 8px;
      overflow: hidden;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    }

    .scene-svg {
      display: block;
      width: 100%;
      height: auto;
    }

    /* Motion Transitions */
    .actor-group {
      transition: transform 0.75s cubic-bezier(0.2, 0.85, 0.35, 1.05);
    }

    .blast-group {
      transition: opacity 0.4s ease-out, transform 0.4s ease-out;
      transform-origin: 275px 135px;
      opacity: 0;
      transform: scale(0.2);
    }

    .blast-group.active {
      opacity: 1;
      transform: scale(1.15);
    }

    /* Cards Grid */
    .cards-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
      width: 100%;
    }

    .stat-card {
      background: #ffffff;
      border-radius: 8px;
      padding: 10px 12px;
      border: 1px solid #e2e8f0;
      border-left-width: 4px;
      display: flex;
      flex-direction: column;
      gap: 4px;
      box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
    }

    .stat-card.cannon {
      border-left-color: #2563eb;
    }

    .stat-card.ball {
      border-left-color: #059669;
    }

    .stat-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 4px;
    }

    .stat-title {
      font-weight: 700;
      font-size: 13px;
      color: #0f172a;
    }

    .stat-badge {
      font-size: 11px;
      font-weight: 700;
      padding: 2px 7px;
      border-radius: 12px;
      white-space: nowrap;
    }

    .cannon .stat-badge {
      background: #dbeafe;
      color: #1e40af;
    }

    .ball .stat-badge {
      background: #d1fae5;
      color: #065f46;
    }

    .stat-val {
      color: #475569;
      font-size: 12px;
    }

    .stat-formula {
      font-size: 12px;
      font-weight: 700;
      color: #1e293b;
      background: #f1f5f9;
      padding: 4px 8px;
      border-radius: 5px;
      border: 1px solid #e2e8f0;
      margin-top: 2px;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    /* Controls */
    .controls {
      display: flex;
      gap: 10px;
      align-items: center;
      justify-content: center;
    }

    .btn {
      background: #2563eb;
      color: #ffffff;
      border: 1px solid transparent;
      padding: 8px 20px;
      border-radius: 6px;
      font-size: 13.5px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background-color 0.3s ease, opacity 0.3s ease, border-color 0.3s ease;
    }

    .btn:hover {
      background: #1d4ed8;
    }

    .btn:active {
      opacity: 0.85;
    }

    .btn-secondary {
      background: #f1f5f9;
      color: #334155;
      border: 1px solid #cbd5e1;
    }

    .btn-secondary:hover {
      background: #e2e8f0;
      color: #0f172a;
    }

    @media (max-width: 440px) {
      .cards-grid {
        grid-template-columns: 1fr;
        gap: 8px;
      }
      .stat-card {
        padding: 8px 10px;
      }
      .stat-title {
        font-size: 12.5px;
      }
      .stat-formula {
        font-size: 11.5px;
      }
    }
  </style>
</head>
<body>

  <div class="main-wrapper">
    
    <div class="scene-svg-wrapper">
      <svg class="scene-svg" viewBox="0 0 600 240" xmlns="http://www.w3.org/2000/svg">
        <defs>
          
          <linearGradient id="skyGrad" x1="0" y1="0" x2="0" y2="1">
            <stop offset="0%" stop-color="#f0f9ff"/>
            <stop offset="85%" stop-color="#e0f2fe"/>
            <stop offset="100%" stop-color="#bae6fd"/>
          </linearGradient>

          
          <pattern id="groundStripes" width="16" height="16" patternUnits="userSpaceOnUse" patternTransform="rotate(45)">
            <rect width="8" height="16" fill="#94a3b8"/>
            <rect x="8" width="8" height="16" fill="#8293a7"/>
          </pattern>

          
          <marker id="arrowHeadLeft" markerWidth="7" markerHeight="7" refX="1" refY="3.5" orient="auto">
            <polygon points="7,0 0,3.5 7,7" fill="#dc2626"/>
          </marker>

          
          <marker id="arrowHeadRight" markerWidth="7" markerHeight="7" refX="6" refY="3.5" orient="auto">
            <polygon points="0,0 7,3.5 0,7" fill="#dc2626"/>
          </marker>

          
          <marker id="blueHeadLeft" markerWidth="6" markerHeight="6" refX="1" refY="3" orient="auto">
            <polygon points="6,0 0,3 6,6" fill="#2563eb"/>
          </marker>

          
          <marker id="greenHeadRight" markerWidth="6" markerHeight="6" refX="5" refY="3" orient="auto">
            <polygon points="0,0 6,3 0,6" fill="#059669"/>
          </marker>
        </defs>

        
        <rect x="0" y="0" width="600" height="180" fill="url(#skyGrad)"/>

        
        <rect x="0" y="180" width="600" height="60" fill="url(#groundStripes)"/>
        <line x1="0" y1="180" x2="600" y2="180" stroke="#64748b" stroke-width="3"/>

        
        <line x1="275" y1="20" x2="275" y2="180" stroke="#94a3b8" stroke-dasharray="3 3" opacity="0.45" stroke-width="1.5"/>
        <text x="275" y="16" text-anchor="middle" font-size="10" font-weight="700" fill="#64748b">Point of Action</text>

        
        <g id="blastGroup" class="blast-group">
          <circle cx="275" cy="135" r="26" fill="#fbbf24" opacity="0.9"/>
          <circle cx="260" cy="125" r="18" fill="#f97316" opacity="0.85"/>
          <circle cx="292" cy="128" r="17" fill="#f97316" opacity="0.85"/>
          <circle cx="275" cy="112" r="15" fill="#ef4444" opacity="0.8"/>
          <circle cx="282" cy="150" r="14" fill="#94a3b8" opacity="0.7"/>
          <circle cx="258" cy="144" r="12" fill="#cbd5e1" opacity="0.6"/>
        </g>

        
        <g id="cannonGroup" class="actor-group">
          
          <text x="185" y="44" text-anchor="middle" font-size="11.5" font-weight="800" fill="#dc2626">F = 1000 N (Recoil)</text>
          <line x1="225" y1="52" x2="145" y2="52" stroke="#dc2626" stroke-width="3" marker-end="url(#arrowHeadLeft)"/>

          
          <line x1="225" y1="70" x2="195" y2="70" stroke="#2563eb" stroke-width="2.5" marker-end="url(#blueHeadLeft)"/>
          <rect x="110" y="80" width="150" height="22" rx="4" fill="#dbeafe" stroke="#bfdbfe" stroke-width="1"/>
          <text x="185" y="95" text-anchor="middle" font-size="11" font-weight="700" fill="#1d4ed8">Small a = 2 m/s²</text>

          
          <text x="210" y="122" text-anchor="middle" font-size="11" font-weight="700" fill="#475569">M = 500 kg</text>

          
          
          <polygon points="195,148 225,148 235,178 185,178" fill="#475569" stroke="#334155" stroke-width="1.5"/>
          
          
          <polygon points="160,118 274,130 270,146 156,134" fill="#1e293b" stroke="#0f172a" stroke-width="1.5"/>
          <ellipse cx="272" cy="138" rx="4" ry="8" fill="#0f172a"/>
          
          <line x1="188" y1="121" x2="185" y2="137" stroke="#64748b" stroke-width="2"/>
          <line x1="230" y1="125" x2="227" y2="141" stroke="#64748b" stroke-width="2"/>
          
          
          <circle cx="210" cy="160" r="20" fill="#64748b" stroke="#1e293b" stroke-width="2.5"/>
          <line x1="210" y1="140" x2="210" y2="180" stroke="#334155" stroke-width="2"/>
          <line x1="190" y1="160" x2="230" y2="160" stroke="#334155" stroke-width="2"/>
          <line x1="196" y1="146" x2="224" y2="174" stroke="#334155" stroke-width="1.5"/>
          <line x1="196" y1="174" x2="224" y2="146" stroke="#334155" stroke-width="1.5"/>
          <circle cx="210" cy="160" r="6" fill="#1e293b"/>
          <circle cx="210" cy="160" r="2.5" fill="#cbd5e1"/>
        </g>

        
        <g id="ballGroup" class="actor-group">
          
          <text x="330" y="44" text-anchor="middle" font-size="11.5" font-weight="800" fill="#dc2626">F = 1000 N (Forward)</text>
          <line x1="290" y1="52" x2="370" y2="52" stroke="#dc2626" stroke-width="3" marker-end="url(#arrowHeadRight)"/>

          
          <line x1="290" y1="70" x2="400" y2="70" stroke="#059669" stroke-width="2.5" marker-end="url(#greenHeadRight)"/>
          <rect x="250" y="80" width="160" height="22" rx="4" fill="#d1fae5" stroke="#a7f3d0" stroke-width="1"/>
          <text x="330" y="95" text-anchor="middle" font-size="11" font-weight="700" fill="#047857">Large a = 200 m/s²</text>

          
          <text x="290" y="122" text-anchor="middle" font-size="11" font-weight="700" fill="#475569">m = 5 kg</text>

          
          <circle cx="290" cy="138" r="10" fill="#1e293b" stroke="#0f172a" stroke-width="1.5"/>
          <circle cx="287" cy="134" r="3" fill="#94a3b8" opacity="0.7"/>
        </g>
      </svg>
    </div>

    
    <div class="cards-grid">
      <div class="stat-card cannon">
        <div class="stat-header">
          <span class="stat-title">Heavy Cannon</span>
          <span class="stat-badge">M = 500 kg</span>
        </div>
        <div class="stat-val">Action Force: <strong>F = 1000 N</strong> (Backward)</div>
        <div class="stat-formula">
          <span>a = F / M = 1000 / 500</span>
          <strong>2 m/s²</strong>
        </div>
      </div>

      <div class="stat-card ball">
        <div class="stat-header">
          <span class="stat-title">Light Cannonball</span>
          <span class="stat-badge">m = 5 kg</span>
        </div>
        <div class="stat-val">Reaction Force: <strong>F = 1000 N</strong> (Forward)</div>
        <div class="stat-formula">
          <span>a = F / m = 1000 / 5</span>
          <strong>200 m/s²</strong>
        </div>
      </div>
    </div>

    
    <div class="controls">
      <button id="fireBtn" class="btn" onclick="triggerFire()">▶ Fire Cannon</button>
      <button id="resetBtn" class="btn btn-secondary" onclick="resetState()">↺ Reset</button>
    </div>
  </div>

  <script>
    let fired = false;
    const cannonGroup = document.getElementById('cannonGroup');
    const ballGroup = document.getElementById('ballGroup');
    const blastGroup = document.getElementById('blastGroup');
    const fireBtn = document.getElementById('fireBtn');

    function triggerFire() {
      if (fired) {
        resetState();
        setTimeout(executeFire, 120);
      } else {
        executeFire();
      }
    }

    function executeFire() {
      fired = true;

      // Blast effect
      blastGroup.classList.add('active');
      setTimeout(() => {
        blastGroup.classList.remove('active');
      }, 350);

      // Accelerations scaled proportionally:
      // Cannon recoils slightly left (small a)
      // Cannonball shoots far right (large a)
      cannonGroup.style.transform = 'translateX(-32px)';
      ballGroup.style.transform = 'translateX(200px)';
      fireBtn.textContent = '▶ Fire Again';
    }

    function resetState() {
      fired = false;
      blastGroup.classList.remove('active');
      cannonGroup.style.transform = 'translateX(0px)';
      ballGroup.style.transform = 'translateX(0px)';
      fireBtn.textContent = '▶ Fire Cannon';
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 12px 8px;
    }

    .badge {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 13px;
      font-weight: 700;
      letter-spacing: 0.2px;
      display: flex;
      align-items: center;
      gap: 6px;
      margin-bottom: 6px;
    }
    .badge .eq { color: #0f172a; font-family: 'Courier New', monospace; font-size: 14px; }
    .badge .sub { color: #64748b; font-weight: 600; font-size: 12px; }

    .canvas-container {
      width: 100%;
      max-width: 500px;
      position: relative;
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    svg {
      width: 100%;
      height: auto;
      overflow: visible;
    }

    .btn-group {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      justify-content: center;
      margin-top: 6px;
    }

    .toggle-btn {
      background: #f8fafc;
      border: 1.5px solid #cbd5e1;
      color: #334155;
      font-size: 12px;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.25s ease;
      user-select: none;
    }
    .toggle-btn:hover {
      background: #e2e8f0;
    }
    .toggle-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(2, 132, 199, 0.35);
    }

    /* SVG Transitions */
    .body-a, .body-b, .vector-fba, .vector-fab, .jump-motion {
      transition: opacity 0.35s ease, transform 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
    }

    .dimmed {
      opacity: 0.15 !important;
    }
    .highlighted {
      opacity: 1 !important;
    }
  </style>
</head>
<body>

  
  <div class="badge">
    <span class="eq">F<sub>AB</sub> = −F<sub>BA</sub></span>
    <span class="sub">(Equal &amp; Opposite)</span>
  </div>

  
  <div class="canvas-container">
    <svg viewBox="0 0 520 300" id="diagramSvg">
      <defs>
        
        <marker id="arrow-blue" markerWidth="9" markerHeight="9" refX="7" refY="4.5" orient="auto">
          <polygon points="0,1 8,4.5 0,8" fill="#0284c7"/>
        </marker>
        
        <marker id="arrow-red" markerWidth="9" markerHeight="9" refX="7" refY="4.5" orient="auto">
          <polygon points="0,1 8,4.5 0,8" fill="#ef4444"/>
        </marker>
      </defs>

      
      <line x1="20" y1="260" x2="500" y2="260" stroke="#cbd5e1" stroke-width="2.5" stroke-dasharray="6,6"/>

      
      <g id="bodyBGroup" class="body-b">
        
        <rect id="boxB" x="120" y="215" width="220" height="50" rx="8" fill="#fef2f2" stroke="#f87171" stroke-width="1.5" stroke-dasharray="4,4" opacity="0"/>
        <text id="labelBodyB" x="130" y="232" fill="#ef4444" font-size="11" font-weight="700" opacity="0">Body B: Board</text>

        
        <g id="boardGraphic">
          <rect x="140" y="240" width="180" height="9" rx="4.5" fill="#334155"/>
          <circle cx="175" cy="254" r="6" fill="#64748b"/>
          <circle cx="285" cy="254" r="6" fill="#64748b"/>
          <circle cx="175" cy="254" r="2.5" fill="#0f172a"/>
          <circle cx="285" cy="254" r="2.5" fill="#0f172a"/>
        </g>
      </g>

      
      <g id="bodyAGroup" class="body-a">
        
        <rect id="boxA" x="180" y="35" width="180" height="195" rx="8" fill="#f0f9ff" stroke="#38bdf8" stroke-width="1.5" stroke-dasharray="4,4" opacity="0"/>
        <text id="labelBodyA" x="190" y="52" fill="#0284c7" font-size="11" font-weight="700" opacity="0">Body A: Person</text>

        
        <g id="personGraphic" stroke="#1e2945" stroke-linecap="round" stroke-linejoin="round">
          
          <circle cx="295" cy="80" r="16" fill="#1e2945"/>
          
          <line x1="285" y1="96" x2="250" y2="160" stroke-width="10"/>
          
          <line x1="280" y1="110" x2="335" y2="120" stroke-width="6"/>
          <line x1="335" y1="120" x2="365" y2="105" stroke-width="5"/>
          
          <line x1="250" y1="160" x2="295" y2="195" stroke-width="7"/>
          <line x1="295" y1="195" x2="320" y2="230" stroke-width="6"/>
          
          <line x1="250" y1="160" x2="225" y2="200" stroke-width="7"/>
          <line x1="225" y1="200" x2="230" y2="238" stroke-width="6"/>
        </g>
      </g>

      
      
      <circle cx="230" cy="238" r="4" fill="#0f172a"/>

      
      <g id="vectorFba" class="vector-fba">
        <line x1="230" y1="238" x2="360" y2="238" stroke="#0284c7" stroke-width="4" marker-end="url(#arrow-blue)"/>
        <rect x="250" y="202" width="130" height="22" rx="4" fill="#e0f2fe"/>
        <text x="256" y="217" fill="#0369a1" font-size="12" font-weight="700">F<tspan font-size="9" dy="2">BA</tspan><tspan dy="-2" font-size="11" font-weight="500"> (Board on Feet)</tspan></text>
      </g>

      
      <g id="vectorFab" class="vector-fab">
        <line x1="230" y1="238" x2="100" y2="238" stroke="#ef4444" stroke-width="4" marker-end="url(#arrow-red)"/>
        <rect x="65" y="202" width="130" height="22" rx="4" fill="#fee2e2"/>
        <text x="71" y="217" fill="#b91c1c" font-size="12" font-weight="700">F<tspan font-size="9" dy="2">AB</tspan><tspan dy="-2" font-size="11" font-weight="500"> (Feet on Board)</tspan></text>
      </g>
    </svg>
  </div>

  
  <div class="btn-group">
    <button class="toggle-btn active" id="btnAll" onclick="setMode('all')">All Forces</button>
    <button class="toggle-btn" id="btnVectors" onclick="setMode('vectors')">Action-Reaction</button>
    <button class="toggle-btn" id="btnBodies" onclick="setMode('bodies')">Two Bodies</button>
    <button class="toggle-btn" id="btnJump" onclick="toggleJump()">Simulate Jump</button>
  </div>

  <script>
    let isJumping = false;
    let currentMode = 'all';

    function updateActiveButton(btnId) {
      document.querySelectorAll('.toggle-btn').forEach(b => {
        if (b.id !== 'btnJump') b.classList.remove('active');
      });
      if (btnId) document.getElementById(btnId).classList.add('active');
    }

    function setMode(mode) {
      currentMode = mode;
      updateActiveButton('btn' + mode.charAt(0).toUpperCase() + mode.slice(1));

      const boxA = document.getElementById('boxA');
      const boxB = document.getElementById('boxB');
      const labelA = document.getElementById('labelBodyA');
      const labelB = document.getElementById('labelBodyB');
      const bodyA = document.getElementById('bodyAGroup');
      const bodyB = document.getElementById('bodyBGroup');
      const vecFba = document.getElementById('vectorFba');
      const vecFab = document.getElementById('vectorFab');

      if (mode === 'all') {
        boxA.setAttribute('opacity', '0');
        boxB.setAttribute('opacity', '0');
        labelA.setAttribute('opacity', '0');
        labelB.setAttribute('opacity', '0');
        bodyA.classList.remove('dimmed');
        bodyB.classList.remove('dimmed');
        vecFba.classList.remove('dimmed');
        vecFab.classList.remove('dimmed');
      } else if (mode === 'vectors') {
        boxA.setAttribute('opacity', '0');
        boxB.setAttribute('opacity', '0');
        labelA.setAttribute('opacity', '0');
        labelB.setAttribute('opacity', '0');
        bodyA.classList.add('dimmed');
        bodyB.classList.add('dimmed');
        vecFba.classList.remove('dimmed');
        vecFab.classList.remove('dimmed');
      } else if (mode === 'bodies') {
        boxA.setAttribute('opacity', '1');
        boxB.setAttribute('opacity', '1');
        labelA.setAttribute('opacity', '1');
        labelB.setAttribute('opacity', '1');
        bodyA.classList.remove('dimmed');
        bodyB.classList.remove('dimmed');
        vecFba.classList.add('dimmed');
        vecFab.classList.add('dimmed');
      }
    }

    function toggleJump() {
      const jumpBtn = document.getElementById('btnJump');
      const bodyA = document.getElementById('bodyAGroup');
      const bodyB = document.getElementById('bodyBGroup');
      const vecFba = document.getElementById('vectorFba');
      const vecFab = document.getElementById('vectorFab');

      isJumping = !isJumping;

      if (isJumping) {
        jumpBtn.classList.add('active');
        jumpBtn.textContent = 'Reset';
        // Leap person up-right, board shoots left
        bodyA.style.transform = 'translate(60px, -40px)';
        bodyB.style.transform = 'translate(-70px, 0)';
        vecFba.style.transform = 'translate(60px, -40px)';
        vecFab.style.transform = 'translate(-70px, 0)';
      } else {
        jumpBtn.classList.remove('active');
        jumpBtn.textContent = 'Simulate Jump';
        bodyA.style.transform = 'translate(0, 0)';
        bodyB.style.transform = 'translate(0, 0)';
        vecFba.style.transform = 'translate(0, 0)';
        vecFab.style.transform = 'translate(0, 0)';
      }
    }
  </script>
</body>
</html>

UK-GCSE-SCIENCE-PHYS-FM-02-04

Aligned learning resources

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