In a vacuum near Earth’s surface, objects fall with nearly the same gravitational acceleration regardless of mass. An object twice as massive experiences roughly twice the gravitational force but also has twice the inertia.
Gravity and inertia cancel in acceleration
Newton’s second law says acceleration depends on force divided by mass. For gravitational force near Earth, force is proportional to the object’s mass, so mass cancels from the acceleration.
Why feathers fall slowly in air
Air resistance depends on shape, area and speed as well as mass. A feather experiences substantial drag relative to its weight, while a compact metal ball may have relatively little.
A simple safe demonstration
Drop two similarly shaped balls of different masses from a low height and compare their arrival times. Differences may be difficult to notice. Avoid dropping objects from high locations or near people.
What changes far from Earth
Gravitational acceleration varies with distance from Earth’s center and with location. The equal-fall principle applies when objects are subjected to the same gravitational field and other forces are negligible.
Frequently asked question
Does mass never affect falling motion?
Mass can matter when drag, buoyancy or mutual gravitational attraction are important; the vacuum demonstration isolates gravity.
Leave a Reply