<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Uniform Circular Motion - Velocity & Speed</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: transparent;
      color: #0f172a;
      width: 100%;
      min-height: 100%;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
    }

    .container {
      width: 100%;
      max-width: 620px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }

    .header-text {
      text-align: center;
      font-size: 13px;
      color: #475569;
      font-weight: 500;
    }

    .main-view {
      width: 100%;
      display: flex;
      flex-direction: row;
      align-items: center;
      justify-content: center;
      gap: 12px;
    }

    .track-container {
      width: 100%;
      max-width: 260px;
      aspect-ratio: 1 / 1;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-shrink: 0;
    }

    svg.track-svg {
      width: 100%;
      height: 100%;
      display: block;
      overflow: visible;
      user-select: none;
    }

    .panel {
      flex: 1;
      min-width: 200px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .stat-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 7px 10px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 8px;
    }

    .stat-label {
      font-size: 12px;
      font-weight: 600;
      color: #64748b;
      white-space: nowrap;
    }

    .stat-val {
      font-size: 12px;
      font-weight: 700;
      text-align: right;
    }

    .val-const {
      color: #0284c7;
    }

    .val-dir {
      color: #0f172a;
      font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    }

    .val-changing {
      color: #d97706;
    }

    .info-tip {
      font-size: 11px;
      line-height: 1.35;
      color: #475569;
      background: #f0f9ff;
      border-left: 3px solid #0284c7;
      padding: 6px 8px;
      border-radius: 0 6px 6px 0;
    }

    .controls {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
      width: 100%;
      justify-content: center;
      align-items: center;
    }

    .btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #334155;
      padding: 5px 10px;
      border-radius: 6px;
      font-size: 11px;
      font-weight: 600;
      cursor: pointer;
      user-select: none;
      transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
    }

    .btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .btn.primary {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }

    .btn.primary:hover {
      background: #0369a1;
      border-color: #0369a1;
    }

    @media (max-width: 500px) {
      .main-view {
        flex-direction: column;
        gap: 8px;
      }
      .track-container {
        max-width: 220px;
      }
      .panel {
        width: 100%;
        min-width: unset;
      }
      .stat-card {
        padding: 6px 8px;
      }
      .btn {
        padding: 4px 8px;
        font-size: 10.5px;
      }
    }
  </style>
</head>
<body>

<div class="container">
  <div class="header-text">
    <strong>Uniform Circular Motion</strong>: Tangent Velocity Vector &amp; Speed
  </div>

  <div class="main-view">
    
    <div class="track-container">
      <svg class="track-svg" viewBox="0 0 300 300" aria-label="Circular track with moving car and tangent velocity vector">
        <defs>
          
          <marker id="arrow-active" viewBox="0 0 10 10" refX="7" refY="5" markerWidth="6" markerHeight="6" orient="auto">
            <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#0284c7" />
          </marker>
          
          <marker id="arrow-ghost" viewBox="0 0 10 10" refX="7" refY="5" markerWidth="5" markerHeight="5" orient="auto">
            <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#94a3b8" />
          </marker>
        </defs>

        
        <circle cx="150" cy="150" r="90" fill="none" stroke="#e2e8f0" stroke-width="32" />
        <circle cx="150" cy="150" r="106" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
        <circle cx="150" cy="150" r="74" fill="none" stroke="#cbd5e1" stroke-width="1.5" />
        
        <circle cx="150" cy="150" r="90" fill="none" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="5,5" />

        
        <circle cx="150" cy="150" r="3" fill="#64748b" />
        <text x="150" y="164" font-size="9" fill="#94a3b8" text-anchor="middle" font-weight="600">r = const</text>

        
        
        <g opacity="0.8">
          <line x1="150" y1="60" x2="198" y2="60" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" marker-end="url(#arrow-ghost)" />
          <circle cx="150" cy="60" r="2.5" fill="#94a3b8" />
          <text x="150" y="48" font-size="9.5" font-weight="700" fill="#64748b" text-anchor="middle">12:00 (East)</text>
        </g>

        
        <g opacity="0.8">
          <line x1="240" y1="150" x2="240" y2="198" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" marker-end="url(#arrow-ghost)" />
          <circle cx="240" cy="150" r="2.5" fill="#94a3b8" />
          <text x="248" y="153" font-size="9.5" font-weight="700" fill="#64748b" text-anchor="start">3:00 (South)</text>
        </g>

        
        <g opacity="0.8">
          <line x1="150" y1="240" x2="102" y2="240" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" marker-end="url(#arrow-ghost)" />
          <circle cx="150" cy="240" r="2.5" fill="#94a3b8" />
          <text x="150" y="258" font-size="9.5" font-weight="700" fill="#64748b" text-anchor="middle">6:00 (West)</text>
        </g>

        
        <g opacity="0.8">
          <line x1="60" y1="150" x2="60" y2="102" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" marker-end="url(#arrow-ghost)" />
          <circle cx="60" cy="150" r="2.5" fill="#94a3b8" />
          <text x="52" y="153" font-size="9.5" font-weight="700" fill="#64748b" text-anchor="end">9:00 (North)</text>
        </g>

        
        <g id="rotGroup" transform="rotate(0, 150, 150)">
          
          <line x1="150" y1="60" x2="204" y2="60" stroke="#0284c7" stroke-width="3" marker-end="url(#arrow-active)" />
          <text x="208" y="56" font-size="11" font-weight="800" fill="#0284c7">v</text>

          
          <line x1="150" y1="150" x2="150" y2="60" stroke="#0284c7" stroke-width="1" stroke-dasharray="2,2" opacity="0.4" />

          
          
          <rect x="139" y="49" width="6" height="3" rx="1" fill="#334155" />
          <rect x="155" y="49" width="6" height="3" rx="1" fill="#334155" />
          <rect x="139" y="68" width="6" height="3" rx="1" fill="#334155" />
          <rect x="155" y="68" width="6" height="3" rx="1" fill="#334155" />
          
          <rect x="136" y="52" width="28" height="16" rx="4" fill="#0f172a" stroke="#334155" stroke-width="1" />
          
          <rect x="142" y="55" width="13" height="10" rx="2" fill="#38bdf8" />
          
          <circle cx="163" cy="54.5" r="1.2" fill="#fef08a" />
          <circle cx="163" cy="65.5" r="1.2" fill="#fef08a" />
        </g>
      </svg>
    </div>

    
    <div class="panel">
      <div class="stat-card">
        <span class="stat-label">Speed (|v|)</span>
        <span class="stat-val val-const">10 m/s (Constant)</span>
      </div>
      <div class="stat-card">
        <span class="stat-label">Direction</span>
        <span class="stat-val val-dir" id="dirText">East &rarr;</span>
      </div>
      <div class="stat-card">
        <span class="stat-label">Velocity (v)</span>
        <span class="stat-val val-changing">Continuously Changing</span>
      </div>
      <div class="info-tip">
        Because direction turns continuously along the circle, <strong>velocity changes</strong> even while <strong>speed remains constant</strong>.
      </div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn primary" id="playBtn" onclick="togglePlay()">&#10074;&#10074; Pause</button>
    <button class="btn" onclick="jumpTo(0)">12 o'clock (East)</button>
    <button class="btn" onclick="jumpTo(90)">3 o'clock (South)</button>
    <button class="btn" onclick="jumpTo(180)">6 o'clock (West)</button>
    <button class="btn" onclick="jumpTo(270)">9 o'clock (North)</button>
  </div>
</div>

<script>
  let angle = 0;
  let isPlaying = true;
  let lastTime = null;
  const speedDegPerSec = 45; // 8 seconds per full revolution

  const rotGroup = document.getElementById('rotGroup');
  const dirText = document.getElementById('dirText');
  const playBtn = document.getElementById('playBtn');

  function getDirectionName(deg) {
    const d = (deg % 360 + 360) % 360;
    if (d >= 337.5 || d < 22.5) return 'East \u2192';
    if (d >= 22.5 && d < 67.5) return 'South-East \u2198';
    if (d >= 67.5 && d < 112.5) return 'South \u2193';
    if (d >= 112.5 && d < 157.5) return 'South-West \u2199';
    if (d >= 157.5 && d < 202.5) return 'West \u2190';
    if (d >= 202.5 && d < 247.5) return 'North-West \u2196';
    if (d >= 247.5 && d < 292.5) return 'North \u2191';
    return 'North-East \u2197';
  }

  function updateView() {
    rotGroup.setAttribute('transform', `rotate(${angle}, 150, 150)`);
    dirText.textContent = getDirectionName(angle);
  }

  function loop(time) {
    if (!lastTime) lastTime = time;
    const dt = (time - lastTime) / 1000;
    lastTime = time;

    if (isPlaying) {
      angle = (angle + speedDegPerSec * dt) % 360;
      updateView();
    }
    requestAnimationFrame(loop);
  }

  function togglePlay() {
    isPlaying = !isPlaying;
    playBtn.innerHTML = isPlaying ? '&#10074;&#10074; Pause' : '&#9654; Play';
  }

  function jumpTo(deg) {
    angle = deg;
    updateView();
  }

  updateView();
  requestAnimationFrame(loop);
</script>

</body>
</html>

Uniform Circular Motion: Moving in a Circle at Constant Speed

<!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: #1e2945;
      background: transparent;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      gap: 12px;
    }

    .cards-row {
      display: flex;
      flex-direction: row;
      gap: 12px;
      width: 100%;
      max-width: 640px;
      flex: 1;
    }

    .concept-card {
      flex: 1;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      border-radius: 12px;
      padding: 14px 10px;
      background: #ffffff;
      transition: border-color 0.2s ease;
    }

    .scalar-card {
      border: 2px solid #f59e0b;
      background: #fffdfa;
    }

    .vector-card {
      border: 2px solid #0284c7;
      background: #f8fcff;
    }

    .card-header {
      text-align: center;
      margin-bottom: 6px;
    }

    .card-title {
      font-size: 17px;
      font-weight: 800;
      letter-spacing: -0.01em;
    }

    .scalar-title { color: #b45309; }
    .vector-title { color: #0369a1; }

    .card-type {
      font-size: 12px;
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      opacity: 0.8;
    }

    .vis-box {
      width: 100%;
      height: 130px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    .speedo-svg {
      width: 130px;
      height: 105px;
    }

    .car-stage {
      width: 130px;
      height: 130px;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    }

    .labels-box {
      width: 100%;
      display: flex;
      flex-direction: column;
      gap: 6px;
      margin-top: 6px;
    }

    .badge {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      padding: 6px 10px;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 700;
      text-align: center;
    }

    .badge-scalar {
      background: #fef3c7;
      color: #92400e;
      border: 1px solid #fde68a;
    }

    .badge-vector-mag {
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #bae6fd;
    }

    .badge-vector-dir {
      background: #0284c7;
      color: #ffffff;
      border: 1px solid #0284c7;
      transition: background-color 0.2s;
    }

    .controls-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      width: 100%;
      max-width: 640px;
      background: #f1f5f9;
      padding: 6px 10px;
      border-radius: 10px;
    }

    .ctrl-label {
      font-size: 12px;
      font-weight: 700;
      color: #475569;
      text-transform: uppercase;
    }

    .dir-btn {
      flex: 1;
      max-width: 70px;
      padding: 6px 0;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      background: #ffffff;
      font-size: 13px;
      font-weight: 700;
      color: #334155;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      transition: all 0.15s ease;
      user-select: none;
    }

    .dir-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 1px 3px rgba(2, 132, 199, 0.3);
    }

    @media (max-width: 480px) {
      body { padding: 8px; gap: 8px; }
      .cards-row { gap: 8px; }
      .concept-card { padding: 10px 6px; }
      .card-title { font-size: 15px; }
      .card-type { font-size: 11px; }
      .vis-box { height: 110px; }
      .speedo-svg { width: 110px; height: 90px; }
      .car-stage { width: 110px; height: 110px; }
      .badge { font-size: 11.5px; padding: 5px 6px; }
      .dir-btn { font-size: 12px; padding: 5px 0; }
    }
  </style>
</head>
<body>

  <div class="cards-row">
    
    <div class="concept-card scalar-card">
      <div class="card-header">
        <div class="card-title scalar-title">Speed</div>
        <div class="card-type">Scalar</div>
      </div>

      <div class="vis-box">
        <svg class="speedo-svg" viewBox="0 0 120 95">
          
          <path d="M 20 80 A 42 42 0 1 1 100 80" fill="none" stroke="#fed7aa" stroke-width="10" stroke-linecap="round" />
          
          <path d="M 20 80 A 42 42 0 0 1 60 18" fill="none" stroke="#f59e0b" stroke-width="10" stroke-linecap="round" />
          
          <line x1="20" y1="80" x2="27" y2="75" stroke="#b45309" stroke-width="2" />
          <line x1="60" y1="18" x2="60" y2="26" stroke="#b45309" stroke-width="2.5" />
          <line x1="100" y1="80" x2="93" y2="75" stroke="#b45309" stroke-width="2" />
          
          <text x="60" y="58" text-anchor="middle" font-size="16" font-weight="800" fill="#78350f">20</text>
          <text x="60" y="72" text-anchor="middle" font-size="10" font-weight="700" fill="#b45309">m/s</text>
          
          <circle cx="60" cy="80" r="5" fill="#78350f" />
          <line x1="60" y1="80" x2="60" y2="28" stroke="#78350f" stroke-width="3" stroke-linecap="round" />
        </svg>
      </div>

      <div class="labels-box">
        <div class="badge badge-scalar">Magnitude only</div>
      </div>
    </div>

    
    <div class="concept-card vector-card">
      <div class="card-header">
        <div class="card-title vector-title">Velocity</div>
        <div class="card-type">Vector</div>
      </div>

      <div class="vis-box">
        <div class="car-stage" id="carStage">
          <svg viewBox="0 0 100 100" width="100" height="100">
            
            <defs>
              <marker id="arrowhead" markerWidth="6" markerHeight="6" refX="4" refY="3" orient="auto">
                <polygon points="0 0, 6 3, 0 6" fill="#0284c7" />
              </marker>
            </defs>
            <line x1="50" y1="46" x2="50" y2="10" stroke="#0284c7" stroke-width="4" stroke-linecap="round" marker-end="url(#arrowhead)" />
            
            
            <rect x="36" y="46" width="28" height="42" rx="6" fill="#0284c7" />
            
            <path d="M 39 58 L 61 58 L 58 50 L 42 50 Z" fill="#bae6fd" />
            
            <rect x="40" y="76" width="20" height="4" rx="1.5" fill="#bae6fd" />
            
            <rect x="32" y="50" width="4" height="9" rx="2" fill="#1e2945" />
            <rect x="64" y="50" width="4" height="9" rx="2" fill="#1e2945" />
            <rect x="32" y="74" width="4" height="9" rx="2" fill="#1e2945" />
            <rect x="64" y="74" width="4" height="9" rx="2" fill="#1e2945" />
            
            <circle cx="40" cy="47" r="2" fill="#fef08a" />
            <circle cx="60" cy="47" r="2" fill="#fef08a" />
          </svg>
        </div>
      </div>

      <div class="labels-box">
        <div class="badge badge-vector-mag">Magnitude: 20 m/s</div>
        <div class="badge badge-vector-dir" id="dirBadge">Direction: North</div>
      </div>
    </div>
  </div>

  
  <div class="controls-bar">
    <span class="ctrl-label">Turn Car:</span>
    <button class="dir-btn active" data-dir="North" data-rot="0">↑ N</button>
    <button class="dir-btn" data-dir="East" data-rot="90">→ E</button>
    <button class="dir-btn" data-dir="South" data-rot="180">↓ S</button>
    <button class="dir-btn" data-dir="West" data-rot="270">← W</button>
  </div>

  <script>
    const carStage = document.getElementById('carStage');
    const dirBadge = document.getElementById('dirBadge');
    const buttons = document.querySelectorAll('.dir-btn');

    buttons.forEach(btn => {
      btn.addEventListener('click', () => {
        buttons.forEach(b => b.classList.remove('active'));
        btn.classList.add('active');

        const deg = btn.getAttribute('data-rot');
        const dir = btn.getAttribute('data-dir');

        carStage.style.transform = `rotate(${deg}deg)`;
        dirBadge.textContent = `Direction: ${dir}`;
      });
    });
  </script>
</body>
</html>

UK-GCSE-SCIENCE-PHYS-FM-01-03

Aligned learning resources

Related diagrams