π― Projectile Motion Calculator
Solve range, height, time and velocity β interactive animated trajectory, planet selector, and full step-by-step working
Projectile Motion Equations β Complete Formula Reference
Projectile motion separates into two independent components: horizontal (constant velocity) and vertical (constant acceleration due to gravity).
| Quantity | Formula | Notes |
|---|---|---|
| Horiz. velocity | vβ = vβcosΞΈ | Constant throughout flight |
| Initial vert. velocity | vyβ = vβsinΞΈ | At launch |
| Vert. velocity at t | vy = vβsinΞΈ β gt | Decreases with time |
| Horiz. position | x = vβcosΞΈ Β· t | Linear in time |
| Vert. position | y = vβsinΞΈ Β· t β Β½gtΒ² | Parabolic path |
| Time to peak | t_peak = vβsinΞΈ / g | Half of total flight time |
| Maximum height | H = (vβsinΞΈ)Β² / (2g) | At t = t_peak |
| Total flight time | T = 2vβsinΞΈ / g | Same-height launch only |
| Horizontal range | R = vβΒ²sin(2ΞΈ) / g | Same-height landing only |
| Speed at time t | v = β(vβΒ² + vyΒ²) | Pythagorean combination |
How Projectile Motion Works β The Two-Component Method
The key principle: horizontal and vertical motions are completely independent. Solve each separately, then combine.
Velocity stays constant: vβ = vβcosΞΈ
Distance: x = vβ Γ t
Velocity changes: vy = vyβ β gt
Height: y = vyβt β Β½gtΒ²
The range formula R = vβΒ²sin(2ΞΈ)/g is maximized when sin(2ΞΈ) = 1, i.e. when 2ΞΈ = 90Β°, giving ΞΈ = 45Β°. Maximum height is found using H = (vβsinΞΈ)Β²/(2g) β only the vertical velocity component contributes to height. Complementary angles (e.g. 30Β° and 60Β°) produce identical ranges but different heights and flight times.
| Angle ΞΈ | Range (m) | Max Height (m) | Time (s) |
|---|---|---|---|
| 15Β° | 20.39 | 1.34 | 1.05 |
| 30Β° | 35.35 | 5.10 | 2.04 |
| 45Β° β | 40.77 | 10.19 | 2.88 |
| 60Β° | 35.35 | 15.29 | 3.53 |
| 75Β° | 20.39 | 19.05 | 3.93 |
| 90Β° | 0 | 20.39 | 4.08 |
Values for vβ = 20 m/s on Earth (g = 9.81 m/sΒ²)
Why 45Β° Gives Maximum Range β The Mathematics Explained
The range formula is R = vβΒ²sin(2ΞΈ)/g. To maximize R we must maximize sin(2ΞΈ). Since the maximum value of any sine is 1, and sin(2ΞΈ)=1 when 2ΞΈ=90Β°, the optimal angle is ΞΈ = 45Β°, giving Rmax = vβΒ²/g.
| Initial Speed vβ | R_max at 45Β° (m) | R_max at 45Β° (ft) |
|---|---|---|
| 5 m/s | 2.55 | 8.36 |
| 10 m/s | 10.19 | 33.43 |
| 20 m/s | 40.77 | 133.7 |
| 30 m/s | 91.74 | 300.8 |
| 50 m/s | 254.8 | 835.7 |
| 100 m/s | 1,019 | 3,343 |
Projectile Motion on the Moon and Other Planets
Gravity determines everything in projectile motion. On the Moon (g = 1.62 m/sΒ²) the same kick sends a ball 6Γ farther. Use the planet selector above to compare.
| Body | g (m/sΒ²) | Range (m) | Max H (m) | Time (s) |
|---|---|---|---|---|
| π Earth | 9.81 | 40.77 | 10.19 | 2.88 |
| π Moon | 1.62 | 246.9 | 61.73 | 17.42 |
| π΄ Mars | 3.72 | 107.5 | 26.88 | 7.58 |
| π€ Jupiter | 24.79 | 16.14 | 4.03 | 1.14 |
| β« Mercury | 3.70 | 108.1 | 27.03 | 7.62 |
| π‘ Venus | 8.87 | 45.07 | 11.27 | 3.18 |
Values for vβ = 20 m/s, ΞΈ = 45Β°
ποΈ During Apollo 14 (1971), astronaut Alan Shepard hit a golf ball on the Moon. With g = 1.62 m/sΒ², even a moderate swing sent the ball vast distances in the low gravity β he estimated it went "miles and miles."
Projectile Motion in Real Life β Sports, Engineering & Nature
Projectile motion appears everywhere β from a football kick to a water fountain arc. Here are five real applications with worked numbers.
A penalty kick at vβ = 28 m/s, ΞΈ = 16Β° travels 11 m horizontally.
x = vβcosΞΈ Γ t β t = 11 / (28 Γ cos16Β°) = 11 / 26.93 = 0.409 s
y = 28Γsin16Β°Γ0.409 β Β½Γ9.81Γ0.409Β² = 3.14 β 0.82 = 2.32 m β clears a 2.44 m crossbar only slightly. Launch angle matters enormously.
A free throw launched at vβ = 7 m/s, ΞΈ = 51Β° from hβ = 2 m must reach a basket at x = 4.6 m, y = 3.05 m.
t = 4.6 / (7 Γ cos51Β°) = 4.6 / 4.404 = 1.044 s
y = 2 + 7Γsin51Β°Γ1.044 β Β½Γ9.81Γ1.044Β² = 2 + 5.676 β 5.351 = 2.32 m β just below rim. The classic 51Β° "optimal" angle is validated by this calculation.
An athlete leaves the board at vβ = 9.5 m/s, ΞΈ = 22Β°.
R = 9.5Β² Γ sin(44Β°) / 9.81 = 90.25 Γ 0.6947 / 9.81 = 6.39 m
World-class long jumpers achieve 8+ m because their takeoff speed exceeds 10 m/s. Every extra m/s at launch adds roughly 1.5 m to the range.
Decorative fountains are designed using projectile equations to hit a target landing point. A nozzle angled at 60Β° with vβ = 4 m/s:
R = 4Β² Γ sin(120Β°) / 9.81 = 16 Γ 0.866 / 9.81 = 1.41 m
H = (4Γsin60Β°)Β² / (2Γ9.81) = (3.464)Β² / 19.62 = 0.612 m β engineers use these numbers to route water precisely into basins.
This calculator uses simplified physics without air resistance β the standard assumption in introductory physics. Real ballistics software includes drag coefficients, wind, the Coriolis effect, and spin-induced deflection (Magnus effect). For a rifle bullet at vβ = 900 m/s and ΞΈ = 0.5Β°, vacuum range = 900Β² Γ sin(1Β°) / 9.81 = 1,413 m, but actual range is far shorter due to aerodynamic drag.
Common Mistakes in Projectile Motion Problems
These five errors account for the majority of wrong answers in projectile motion problems:
Correct: H = (vβsinΞΈ)Β² / (2g) β only the vertical component lifts the projectile
For vβ=20, ΞΈ=30Β°: Wrong gives H=20.4 m, correct gives H=5.1 m
Correct: Always split first β vβ = vβcosΞΈ (horizontal) and vyβ = vβsinΞΈ (vertical) β then apply kinematic equations to each direction independently
Correct: y = vyβt β Β½gtΒ² β gravity decelerates upward motion (g is magnitude; the minus sign accounts for direction)
Correct: t_peak = vβsinΞΈ/g is time to reach maximum height; total flight T = 2t_peak (for same-height launch). Using t_peak gives half the correct range.
Correct: R = vβΒ²sin(2ΞΈ)/g β the argument is 2ΞΈ, not ΞΈ. At 45Β°: sin(45Β°) = 0.707 vs sin(90Β°) = 1.0 β the wrong formula gives 29% less range.
Frequently Asked Questions
Related Calculators
Data Sources & References
- Projectile motion equations and trajectory: Halliday, D., Resnick, R. & Krane, K.S. (2002). Physics, 5th ed. Wiley. Chapter 4.
- Range and maximum height derivations: Serway, R.A. & Jewett, J.W. (2014). Physics for Scientists and Engineers, 9th ed. Cengage. Chapter 4.3.
- Standard acceleration of gravity g = 9.80665 m/sΒ²: CODATA 2018, NIST SP 961. physics.nist.gov
- Optimal launch angle 45Β° for maximum range on level ground: Halliday, D., Resnick, R. & Krane, K.S. (2002). Physics, 5th ed. Wiley. Chapter 4, Problem 33.