Mechanics 1 - free fall

Galileo's analysis of free fall can be considered the start of modern physics.

Feather free-fall experiment from user teralabUK
http://www.youtube.com/watch?v=4z8g8OSOMzY

My physics playlist: http://www.youtube.com/view_play_list?p=7B0D5AF68906CEFF

Category:

Education

Tags:

• physics
• Galileo
• free
• fall

[handplanty]

But ozmoroid, acceleration is not constant. Galileo was wrong. Heavier objects fall faster, even without neglecting air resistance, because they make the Earth accelerate towards them faster than light objects. You cheat by making them fall at the same time - they'll fall even faster! Don't forget Newton's equation of action = -reaction and F=G*m*M/d², where m is variable between the two objects and, thus, d determines what the acceleration will be.

[ozmoroid]

@handplanty If you assume that the mass of the falling object is subtracted from the total Earth mass then the the relative acceleration is the same (only depends on the total mass in the system). If you don't assume that then the heavier mass does indeed fall a bit faster. 'course at that level of detail the acceleration depends on where you stand while you shoot the video. ;-)

[asdfbobbyasdf]

I feel like if I watch the entire series...then re watch it everything will male more sense.

[livedandletdie]

@handplanty isn't it first and foremost F=(G*mass1*mass2)/r² which only equals Force of Gravity. F=ma is the concept of force on objects moving in relative to eachother.

We can change both of them into another formula G/r²*m1=F1 G/r²*m2=F2 Delta"F" is proportionate to Delta "m". which means a=g and so we're back with g and as we know is the same for all objects falling in the same space on earth.

[transcendentape]

@handplanty Though this comment is a year old, it should not go uncorrected. You are correct that Newton's Law of Universal Gravitation shows the force acting on a falling body increases proportionally to the falling object's mass. However, you have neglected the fact that the force required to accelerate an object also increases proportionally to its mass. F=ma. In a vacuum, the acceleration due to gravity is the same, heavier objects do not fall to the Earth faster.

[handplanty]

@19916718514 Ha, but you forget that the force between attracting bodies is also dependent on the distance between them. In falling, the bodies' relative distance is reduced, thus increasing the force between them ;)

[19916718514]

@handplanty the gravitational force between two or more bodies is dependent on their masses. However, the gravitational acceleration of an attracted body is not dependent on its mass, since a =F/m thus removes the mass (m) of the observe object out of the equation

[TheHomelessCripple]

All this math makes me nostalgic for my high school physics and calculus classes.

[dimbulb23]

@ozmoroid So if you stand too close to the point of impact while taking the video I suppose the speed of the fall would be affected by whether you were wearing shoes or we're barefoot. and steel-toed boots would totally screw up the experiment.

[vargulf19]

Actually I thought Copernicus was the one who basically said all this already but Galileo got famous because of the church contraversy and having the telescope