Free Fall
Without air resistance, all objects fall with the same acceleration.
About this topic
In free fall an object moves under gravity alone, ignoring air resistance. Near Earth's surface all objects accelerate downward at g ≈ 9.8 m/s², regardless of mass, as Galileo argued and astronauts demonstrated by dropping a hammer and feather on the Moon.
After 1 s the speed is about 9.8 m/s, after 2 s about 19.6 m/s, and after 3 s about 29.4 m/s. The distance fallen from rest is s = ½gt², so it grows with the square of time: about 4.9 m after 1 s, 19.6 m after 2 s and 44.1 m after 3 s. The same equations of motion apply, with a = g.
Example: a stone dropped from a cliff takes 3 s to reach the sea, so the cliff is about 44 m high and the stone hits at about 29 m/s. This is a handy way to estimate heights. Astronauts in orbit are in free fall around Earth, which is why they float.
Misconceptions: heavier objects do not fall faster in a vacuum, and everyday differences come from air resistance. Also, an object thrown upward is in free fall too, as soon as it leaves the hand, even while it is still rising.
Key ideas
- g ≈ 9.8 m/s² downward
- Speed increases 9.8 m/s each second
- Mass does not affect fall time
Quick check
Use cases: where Free Fall helps
- Homework: review the key idea behind Free Fall before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Free Fall without notes.
- Visual learning: play with the interactive lab to see how Free Fall changes when you adjust its inputs.
- Teaching a friend: explain Free Fall in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Free Fall?
Without air resistance, all objects fall with the same acceleration.
What will I learn in Free Fall?
g ≈ 9.8 m/s² downward. Speed increases 9.8 m/s each second. Mass does not affect fall time.
Is Free Fall part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Free Fall lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Free Fall?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.