galileo's experiment?

Question

I don't understand something...can someone clear this for me?

so, what galileo did...He dropped 2 objects of different masses which fell down at the same time,which proved that the time of descent was independent of their masses.

But, in that experiment, shouldn't air resistance have slowed down the lighter object because of friction? help!

Answer 1

In Galileo's experiment, the objects were the same size, so as to eliminate the air resistance factor. (Since they were the same size, the air resistance was the same on both objects. Thus, air resistance would not have slowed down the lighter object. Air resistance is not related to mass, only size.) The only difference in the two objects was their masses.

To read more about this experiment, go to http://www.endex.com/gf/buildings/ltpisa/ltpnews/physnews1.htm

Answer 2

Galileo reached his conclusions about the acceleration of gravity from experiments using inclined planes, where things moved slowly enough for him to time (he had only his own pulse as a timer). It's not clear if or when he ever performed the experiment from the Tower of Pisa, but possibly one of his students did it. In Galileo's Daughter, Dava Sobel quotes him discussing the results:
"Aristotle says that a hundred-pound ball falling from a height of a hundred braccia [arm lengths] hits the the ground before a one-pound ball has fallen one braccio. I say they arrive at the same time," Galileo resummarized the dispute in its aftermath. "You find, on making the test, that the larger ball beats the smaller one by two inches. Now, behind those two inches you want to hide Aristotle's ninety-nine braccia and, speaking only of my tiny error, remain silent about his enormous mistake."

So yes, air resistance did interfere with the demonstration It wasn't enough to really disprove Galileo, though some of his opponents apparently maintained it did.

Answer 3

But dramaman, the acceleration is proportional to the NET force per unit mass, and the air force on the lighter ball is a much greater % of the gravitaional acceleration, so clearly the denser of 2 equal size balls will have a greater a value.....

Think of a balloon full of air and a balloon full of water; same size.

Answer 4

If to ball made by steal of different mass is falling from a hight then difference of air resistance will be neglegible. if the dencity of the matarial of the balls are same then the air resistance will be same.

Answer 5

I believe the objects were both spheres of the same size (different material compositions with different weights), so the drag coefficients would be the same.

Answer 6

No
In his experiment he used 2 balls of same size but made out of different materials. He is one of the greatest ever lived. So you need good luck to find fault with this guy.

Answer 7

It probably did. But both objects (different size cannonballs, according to legend) were sufficiently massive that the difference was **much** smaller than anything they could detect.


Doug