Mechanics / gravity / free fall
Heavier Does Not Fall Faster
That a 10 kg ball falls ten times — or at least noticeably — faster than a 1 kg ball. The belief survives the lecture because in air it is often locally true, and no one separates the two effects.
In free fall every mass accelerates at g, because the larger gravitational force on a heavier object is exactly cancelled by its larger inertia. Air resistance — which does not scale with mass — is what separates the feather from the hammer.
The lesson that sent you here
- Motion Does Not Require a Force
That a moving object must have a force acting on it, and that when the force is 'used up' the object stops — the medieval impetus theory, which most students hold walking into their first mechanics class and many still hold walking out.
1 published lesson depends on this concept, which is what moves it up the writing queue. Nothing is hidden behind this page — it has not been written.