{"id":591,"date":"2026-07-17T11:34:31","date_gmt":"2026-07-17T11:34:31","guid":{"rendered":"https:\/\/physicsfundamentalsinfo.com\/blog\/?p=591"},"modified":"2026-07-17T11:34:32","modified_gmt":"2026-07-17T11:34:32","slug":"free-fall-physics","status":"publish","type":"post","link":"https:\/\/physicsfundamentalsinfo.com\/blog\/kinematics\/free-fall-physics\/","title":{"rendered":"Free Fall Physics: Formula & Real Examples"},"content":{"rendered":"\n
Definition<\/div>

\n\nFree fall physics describes any motion in which gravity is the only force acting on an object, so every object accelerates downward at the same rate g \u2014 about 9.81 m\/s\u00b2 on Earth \u2014 no matter how heavy it is. Distance fallen from rest equals half g times time squared; speed equals g times time. Air resistance must be negligible.\n\n<\/p><\/div>\n\n

Hold a coin in one hand and your phone in the other, then open both hands at the same instant. They hit the floor together \u2014 and some part of you still expects the phone to win, because it is roughly forty times heavier.<\/p>\n\n

That instinct is ancient, and it is wrong. Settling it took two thousand years, a set of grooved wooden ramps, and eventually an astronaut standing on the Moon with a hammer in one glove and a falcon feather in the other. The physics that explains all of it fits into two short equations.<\/p>\n\n

What Is Free Fall in Physics?<\/h2>\n\n

Free fall is motion in which gravity is the only force acting on an object. Nothing else \u2014 no air resistance, no rope, no table, no thrust \u2014 is allowed to push or pull on it.<\/p>\n\n

Notice what that definition does not<\/em> say. It says nothing about moving downward, and nothing about starting from rest.<\/p>\n\n

A ball you throw straight up is in free fall from the moment it leaves your fingers until the moment you catch it \u2014 rising, hanging, and dropping. Its speed changes constantly, but throughout that whole flight only gravity acts on it, so it qualifies. The everyday word “falling” is a poor guide here; the physics test is simply what forces are acting?<\/em><\/p>\n\n

And free fall is defined by an acceleration<\/a>, not a speed. An object in free fall does not fall at 9.81 m\/s. It falls with its speed increasing<\/em> by 9.81 m\/s during every second it keeps falling \u2014 a very different claim, and the one students most often garble in an exam.<\/p>\n\n

Run any scenario through the single test below and the answer falls out.<\/p>\n\n

\n\n\n\n\n\n\n\n\n\n\n\n
Scenario<\/th>\nForces acting<\/th>\nFree fall?<\/th>\n<\/tr>\n<\/thead>\n
Ball dropped inside a vacuum tube<\/td>\nGravity only<\/td>\nYes<\/strong> \u2014 the textbook case<\/td>\n<\/tr>\n
Ball thrown straight up, still in the air<\/td>\nGravity only<\/td>\nYes<\/strong> \u2014 rising counts too<\/td>\n<\/tr>\n
Astronaut orbiting inside the ISS<\/td>\nGravity only<\/td>\nYes<\/strong> \u2014 permanently falling<\/td>\n<\/tr>\n
Skydiver in the first moment after jumping<\/td>\nGravity, plus a tiny drag force<\/td>\nNear enough, briefly<\/td>\n<\/tr>\n
Skydiver at steady terminal velocity<\/td>\nGravity balanced by drag<\/td>\nNo<\/strong> \u2014 zero acceleration<\/td>\n<\/tr>\n
Feather drifting down through air<\/td>\nGravity, and drag almost as large<\/td>\nNo<\/strong> \u2014 drag dominates<\/td>\n<\/tr>\n
Apple sitting on a table<\/td>\nGravity balanced by the normal force<\/td>\nNo<\/strong> \u2014 not even moving<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n

The free-fall test: strip away every force except gravity. If anything is left, it is not free fall.<\/p>\n\n

The Free Fall Formulas<\/h2>\n\n

Free fall from rest is described by three equations, and each one answers a different question. Start with the distance fallen after a given time:<\/p>\n\n

h = \u00bdgt\u00b2<\/div>\n\n

Then the speed reached after that time:<\/p>\n\n

v = gt<\/div>\n\n

And the one that skips time entirely, when you know the height but not the clock:<\/p>\n\n

v\u00b2 = 2gh<\/div>\n\n

Every symbol, with its SI unit:<\/p>\n\n