Does weight affect an object's speed during free fall?

AI Thread Summary
All objects fall at the same speed in a vacuum, regardless of their weight, as demonstrated by the example of a feather and a bowling ball dropped on the moon. The confusion arises from the definition of weight, which is the force due to gravity and is dependent on mass. While the bowling ball has greater mass and therefore greater weight, both objects experience the same acceleration due to gravity. This is explained by Newton's second law, where the acceleration remains constant despite differences in weight. In the absence of air resistance, all objects fall at the same rate.
musicboy
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Hi there
Just wondering: all objects fall at the same speed, right(not taking into account air resistance)? So if I dropped a feather and a bowling ball on the moon, they'd fall at the same speed. So far so good.
But my physics book's definition of weight is "The weight of an object is the force that acts on it because of gravity; Weight = Mass x Acceleration due to gravity" .
The bowling ball's mass is clearly greater than the feather's, so therefore it's weight and therefore pull of gravity on it must be different, resulting in a different speed...
Confused!
Any help much appreciated :)
 
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hi musicboy! :smile:
musicboy said:
… my physics book's definition of weight is "The weight of an object is the force that acts on it because of gravity; Weight = Mass x Acceleration due to gravity" .
The bowling ball's mass is clearly greater than the feather's, so therefore it's weight and therefore pull of gravity on it must be different, resulting in a different speed...

yes, the force of gravity on it is greater (Mg > mg)

but force = mass times acceleration (that's Newton's second law),

so the accelerations are the same (A = Mg/M, a = mg/m) :wink:
 
musicboy said:
Weight = Mass x Acceleration...

The bowling ball's mass is clearly greater than the feather's, so therefore it's weight and therefore pull of gravity on it must be different,
You have the equation right there. If you change Weight & Mass by the same factor, Acceleration stays the same.

musicboy said:
resulting in a different speed...
The terminal speed, where air resistance = weight, is different. But in vacuum they fall the same.
 
To add to what A.T. And Tiny-Tim have said... There's an FAQ on this at https://www.physicsforums.com/forumdisplay.php?f=209
 
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Gotcha :)
Thanks very much all of you for quick and concise replies.
Have a good day :D
 

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