Q.The position vector of a particle has length 1 m and makes 30° with the x-axis. What are the lengths of the x and y components of the position vector?
Imagine pushing a heavy box across the floor at an angle — not straight forward, but slightly downward. Some of your effort moves the box forward, and some presses it into the floor. The force you apply is a single vector, but its effect splits into two independent directions: horizontal and vertical.
That splitting is vector component extraction. Any vector can be seen as the sum of two (or three) simpler vectors pointing along chosen reference directions — usually the coordinate axes. Each of those simpler vectors is a component.
Note
"Component" means "a part of a whole." In vectors, the components are the parts that add up to give the original vector.
The Precise Statement
Given a vector v in a plane, and perpendicular axes x and y, the components of v are its projections onto those axes:
v=vxi^+vyj^
where i^ and j^ are unit vectors along the x and y axes, and vx, vy are scalar components (numbers, possibly negative).
If v makes an angle θ from the positive x-axis, then:
vx=∣v∣cosθandvy=∣v∣sinθ
Component along an axis=(magnitude of vector)×cos(angle between vector and that axis)
Why This Works: The Geometry
Draw a vector from the origin. Drop a perpendicular from its tip to the x-axis — that gives vx. Drop another to the y-axis — that gives vy. The original vector is the diagonal of the rectangle formed by vx and vy. This is the Pythagorean theorem in reverse: if you know the hypotenuse and one angle, trigonometry gives you the legs.
A Concrete Example
A force of 10 N acts at 30∘ above the horizontal.
Fx=10cos30∘=10×23=53≈8.66 N
Fy=10sin30∘=10×21=5 N
So the force vector is 8.66i^+5j^ N.
Watch out
A common mistake: using sin for the horizontal component and cos for the vertical. Check: if the angle is measured from the x-axis, the side adjacent to it is along x — that's cos; the opposite side is along y — that's sin.
Why This Matters
Component extraction is the single most useful operation in vector physics. It lets you add vectors by adding their components (much easier than geometry), apply Newton's laws separately in each direction, and analyze 2D motion (projectiles, inclined planes). Without components you'd draw parallelograms every time; with them, it's just arithmetic.
The deeper reason it works: every vector is a sum of perpendicular pieces, and those pieces are independent — changing one doesn't affect the other. That independence lets you treat the x- and y-directions as separate problems, then combine the results.
Vector component extraction is the art of breaking a single vector into its perpendicular parts, so you can work with each separately.
Resolving a vector into its perpendicular components is taught in the CBSE Class 11 Physics and Mathematics vector chapters and revisited in Class 12 Vector Algebra, making "vector components formula with examples" one of the most searched topics across both subjects. This same component method is essential for solving projectile motion and inclined-plane problems in JEE Main and NEET Physics.
Resolve using lx=lcosθ, ly=lsinθ.
✓Final answer
lx=23≈0.866 m, ly=0.5 m
Step 1. Given magnitude l=1 m and angle θ=30° with the x-axis.