How it works
In free fall, every object accelerates downward at g ≈ 9.81 m/s², regardless of its mass — Galileo's great insight. A hammer and a feather fall together on the Moon; on Earth only air resistance separates them.
Fall time grows with the square root of height: falling 4× higher takes only 2× longer, but you hit the ground 2× faster. That square-root relationship is why 'just a bit higher' is so much more dangerous than it feels.
A 10 m drop (a 3-storey window) takes just 1.43 seconds and ends at 50 km/h — about the speed of a serious urban car crash. Free-fall numbers are the fastest way to build genuine respect for heights.
Use it in real life
Home safety: understanding that a fall from 3 m already means hitting the ground at 28 km/h explains why ladder falls are a leading cause of serious home injuries.
Estimating depth: drop a stone into a well and count seconds — depth ≈ 4.9 × t². Two seconds means roughly 20 metres.
Amusement parks: drop towers are pure free-fall physics; a 60 m tower delivers about 3.5 seconds of weightlessness and a 124 km/h peak.
Frequently asked questions
Do heavy objects fall faster than light ones?
Not in a vacuum — all objects accelerate at the same rate g. In air, heavier and denser objects are less affected by drag, so in practice a bowling ball beats a balloon.
How fast does a human fall after 3 seconds?
Ignoring air resistance, v = g·t ≈ 29 m/s (106 km/h) after 3 seconds, having fallen about 44 m. Real skydivers reach a terminal velocity near 200 km/h where drag balances gravity.
What does this calculator ignore?
Air resistance. For short drops of dense objects the error is small; for long falls or light objects (paper, leaves), drag dominates and actual speeds are much lower.