Understanding Projectile Motion — Free Interactive Simulator
Projectile motion describes an object moving through the air under gravity alone, tracing a parabolic path. This free simulator lets you launch projectiles at any angle and speed, then computes range, maximum height, and time of flight from the standard kinematic equations — with optional air resistance and lunar or Martian gravity.
What is the range formula for projectile motion?
For a projectile launched from ground level with initial velocity v at angle θ, the horizontal range is R = v²·sin(2θ) / g. The maximum range on flat ground occurs at 45°, because sin(2×45°) = 1. Complementary angles such as 30° and 60° produce the same range but with different heights — the lower angle gives a flatter, faster path and the higher angle a taller, slower arc.
Key Projectile Motion Equations (Featured Snippet)
| Quantity | Formula (SI) | Symbol & Unit |
|---|---|---|
| Range (ground launch) | R = v²·sin(2θ) / g | R, m |
| Maximum height | H = v²·sin²(θ) / (2g) | H, m |
| Time of flight (ground) | T = 2v·sin(θ) / g | T, s |
| Time to peak | tp = v·sin(θ) / g | tp, s |
| Horizontal velocity | Vx = v·cos(θ) | Vx, m/s |
| Vertical velocity | Vy = v·sin(θ) − g·t | Vy, m/s |
| Impact speed (from height) | vf = √(v² + 2gh) | vf, m/s |
| Drag force (with air) | Fd = ½·Cd·ρ·A·v² | Fd, N |
How do you calculate maximum height and time of flight?
The maximum height reached by a projectile is H = v²·sin²(θ) / (2g). At this point, the vertical velocity component becomes zero while the horizontal component continues unchanged. The time of flight for a ground-level launch is T = 2v·sin(θ) / g. When launching from height h, the time of flight increases because the projectile has farther to fall, and the range increases accordingly.
Why are horizontal and vertical motion independent?
The horizontal velocity Vx = v·cos(θ) remains constant throughout the flight (in the absence of air resistance), while the vertical velocity Vy = v·sin(θ) − gt changes linearly due to gravitational acceleration. Because gravity acts only vertically, the two motions evolve independently — a bullet fired horizontally and one dropped from the same height strike the ground at exactly the same time. The impact velocity follows from the Pythagorean theorem on the final velocity components.
How does air resistance change the trajectory?
In reality, air resistance (drag) significantly affects projectile trajectories. The drag force Fd = ½·Cd·ρ·A·v² acts opposite to the velocity vector, reducing both range and maximum height while breaking the symmetry of the parabolic path. The optimal launch angle shifts below 45° when drag is present. This simulator lets you toggle air resistance on and off to compare ideal and realistic trajectories side by side.
How do I use this projectile motion simulator?
In Simulate mode, adjust angle, velocity, and height using sliders or steppers, then press Fire to watch the projectile trace its trajectory. Switch between Earth, Moon, and Mars gravity, toggle Air Resistance, or flip to Imperial units. Open Show Calculations for a step-by-step derivation in SI. Use Explore mode for 12 concept cards, Practice for unlimited random problems, and Quiz for 5-question timed assessments.
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