Free Fall Simulator
Gravitational Acceleration • Kinematics • Terminal Velocity — Simulate • Explore • Practice • Quiz
Understanding Free Fall and Gravitational Acceleration
Free fall is one of the most important concepts in classical mechanics. It describes the motion of an object falling solely under the influence of gravity, with no other forces acting on it. In the ideal case (a vacuum), all objects fall at the same rate regardless of their mass or shape. This remarkable insight, attributed to Galileo Galilei, overturned centuries of Aristotelian thinking and laid the foundation for Newtonian mechanics.
The acceleration due to gravity (denoted g) is approximately 9.81 m/s² at Earth's surface. This means a freely falling object increases its speed by 9.81 metres per second every second. This value varies slightly depending on altitude, latitude, and local geological conditions — from about 9.78 m/s² at the equator to 9.83 m/s² at the poles. On other celestial bodies, g differs dramatically: 1.62 m/s² on the Moon, 3.72 m/s² on Mars, and a crushing 24.79 m/s² on Jupiter.
The Kinematic Equations of Free Fall
For an object released from rest at height h, three key equations govern its motion. The distance fallen is given by s = ½gt², showing that displacement increases with the square of time — a parabolic relationship that proves the object is accelerating, not moving at constant speed. The instantaneous velocity at time t is v = gt, a linear relationship. Combining these gives the time-independent equation v² = 2gs, which relates velocity directly to distance fallen without needing to know the elapsed time. To find the total fall time from height h, rearrange the distance equation: t = √(2h/g).
Galileo's Experiment and the Universality of Free Fall
Galileo's famous thought experiment (and later physical experiments with inclined planes) demonstrated that in the absence of air resistance, a feather and a hammer fall at exactly the same rate. This was dramatically confirmed on the Moon during the Apollo 15 mission in 1971, when astronaut David Scott dropped a hammer and a falcon feather simultaneously — both hit the lunar surface at the same instant. This principle is fundamental to Einstein's equivalence principle and forms the basis of general relativity.
Air Resistance and Terminal Velocity
In the real world, air resistance (drag) opposes the motion of falling objects. The drag force increases with velocity until it equals the gravitational force, at which point the object reaches terminal velocity and stops accelerating. A skydiver reaches approximately 55 m/s (200 km/h) in the spread-eagle position, while a peregrine falcon can dive at over 90 m/s. Parachutes exploit this principle by increasing drag area to reduce terminal velocity to a safe landing speed of about 5 m/s.
Who Uses This Simulator?
This free fall simulator is designed for engineering students, physics learners, technical education trainees, and educators who need to visualise gravitational acceleration, practise kinematics calculations, and understand the relationship between distance, velocity, and time during free fall. The multi-planet comparison feature makes it especially useful for aerospace and planetary science courses.
Explore Related Simulators
If you found this free fall simulator helpful, explore our Boyle's Law simulator, Charles's Law simulator, Thermal Expansion simulator, and Thermodynamics Cycles simulator for more hands-on practice.