How to Calculate Magnitude of a Vector

Vector Magnitude Calculator

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Understanding the Magnitude of a Vector

In mathematics and physics, a vector represents a quantity that has both magnitude (size) and direction. The magnitude of a vector is a scalar value that describes the length of the vector from its starting point to its endpoint. It is always a non-negative number.

The Vector Magnitude Formula

The magnitude of a vector v with components (vx, vy, vz) is calculated using the distance formula, which is an extension of the Pythagorean theorem. The formula is expressed as:

|v| = √(vx² + vy² + vz²)

If you are working in a 2D space, you simply omit the vz component (set it to zero).

Step-by-Step Calculation Example

Let's calculate the magnitude of a 3D vector where v = (3, -4, 5):

  1. Square each component: 3² = 9, (-4)² = 16, 5² = 25.
  2. Sum the squares: 9 + 16 + 25 = 50.
  3. Take the square root: √50 ≈ 7.071.

The magnitude of the vector is approximately 7.071 units.

Why is Vector Magnitude Important?

Calculating magnitude is crucial in various fields:

  • Physics: Determining the total force, velocity, or acceleration acting on an object.
  • Engineering: Structural analysis and electrical field calculations.
  • Navigation: Calculating the direct distance (displacement) between two geographic points.
  • Computer Graphics: Normalizing vectors for lighting calculations and 3D rendering.
function calculateVectorMagnitude() { var x = parseFloat(document.getElementById('inputX').value); var y = parseFloat(document.getElementById('inputY').value); var z = parseFloat(document.getElementById('inputZ').value); // Default to 0 if input is empty or invalid if (isNaN(x)) x = 0; if (isNaN(y)) y = 0; if (isNaN(z)) z = 0; // Magnitude calculation: sqrt(x^2 + y^2 + z^2) var sumOfSquares = (x * x) + (y * y) + (z * z); var magnitude = Math.sqrt(sumOfSquares); // Display Logic var resultDiv = document.getElementById('magnitudeOutput'); var resultText = document.getElementById('calcResult'); var formulaText = document.getElementById('calcFormula'); resultDiv.style.display = 'block'; if (magnitude % 1 === 0) { resultText.innerHTML = magnitude.toString(); } else { resultText.innerHTML = magnitude.toFixed(4); } formulaText.innerHTML = "Calculation: √(" + x + "² + " + y + "² + " + z + "²) = √" + sumOfSquares; // Scroll smoothly to result resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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