Motion in 2D NEET Notes 2026 – Free PDF Download
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🎯 MOTION IN 2D · Projectile & Circular Motion
Projectile motion • Circular motion • Relative velocity in 2D • NEET shortcuts
🎯 PROJECTILE MOTION (Oblique Projection)
Motion under constant gravity, neglecting air resistance. Initial velocity u at angle θ with horizontal.
Components: uₓ = u cosθ, uᵧ = u sinθ
Time of flight (T): T = 2u sinθ / g
Max height (H): H = u² sin²θ / (2g)
Range (R): R = u² sin2θ / g
✏️ Projectile trajectory
Parabolic path: y = x tanθ – (g x²)/(2u² cos²θ)
🏹 HORIZONTAL PROJECTION (from height)
Initial velocity horizontal: uₓ = u, uᵧ = 0
Time to hit ground: t = √(2h/g)
Horizontal range: R = u × t = u √(2h/g)
Velocity at time t: v = √(u² + g²t²)
🔄 UNIFORM CIRCULAR MOTION (UCM)
Angular displacement: Δθ (radians)
Angular velocity: ω = Δθ/Δt = v/r (rad/s)
Centripetal acceleration: ac = v²/r = ω²r
Centripetal force: Fc = mv²/r = mω²r
🎡 Circular motion doodle
v = ωr, T = 2π/ω, f = 1/T
🚤 RELATIVE MOTION IN 2D
Velocity of A w.r.t B: vAB = vA – vB
River-boat problems: vboat/ground = vboat/water + vwater/ground
Minimum time to cross river: drift = (vriver × width) / vboat (perpendicular crossing)
✏️ River-boat vector diagram
💡 NEET TIPS & SHORTCUTS
- In projectile, velocity at any time: v = √(uₓ² + (uᵧ – gt)²)
- Angle of projection for max range: 45° (sin90=1).
- For same range, two angles: θ and 90°–θ, and time of flight differ: T₁ = 2u sinθ/g, T₂ = 2u cosθ/g.
- In UCM, ac is constant in magnitude but direction changes → not uniform acceleration.
- For a particle moving in a circle with constant speed, no tangential acceleration, only radial.
⚠️ COMMON MISTAKES
- Taking vertical acceleration as zero in projectile – it's always g downwards.
- Confusing centripetal force with centrifugal (fictitious).
- For river crossing, not resolving velocity components correctly.
- Using range formula for horizontal projection directly.
📌 QUICK REVISION CARD
Projectile: T = 2u sinθ/g, H = u² sin²θ/2g, R = u² sin2θ/g
Horizontal projection: t = √(2h/g), R = u√(2h/g)
UCM: ac = v²/r = ω²r, Fc = mv²/r
Relative velocity: vAB = vA – vB
