Does Mass Matter in Free Fall?

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SUMMARY

The discussion centers on the concept of free fall and the relationship between mass, force, and acceleration. Participants clarify that in free fall, all objects, regardless of mass, accelerate at the same rate due to gravity, as demonstrated by Galileo's experiments and later confirmed by astronauts on the Moon. The equation F=ma illustrates that while force increases with mass, the acceleration remains constant at approximately 9.8 m/s² when only gravitational force acts on the object. Misunderstandings about mass and free fall are addressed, emphasizing that mass does not affect the rate of fall in a vacuum.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with the equation F=ma (Force equals mass times acceleration)
  • Basic knowledge of gravitational acceleration (g = 9.8 m/s²)
  • Concept of free fall and its implications in physics
NEXT STEPS
  • Explore the implications of Galileo's experiments on modern physics
  • Study the effects of air resistance on falling objects
  • Investigate Einstein's theory of general relativity and its relation to gravity
  • Conduct practical experiments demonstrating free fall with varying masses
USEFUL FOR

Students of physics, educators teaching concepts of motion and gravity, and anyone interested in understanding the principles of free fall and acceleration.

tomlib
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Hello. I read on Wikipedia that when a body is in free fall from zero mass, its mass does not matter and two bodies of different weights will fall at the same speed. I think this is not correct. If I consider that the bodies are in a weightless state and the gravitational force will act on them. This force will be as great as the weight of this body.
If a greater force acts on something, it will most likely move faster. Is my reasoning correct?
 
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The problem is that no force or weight can be measured during pure free fall.
If you could use a measuring device, the fall would not be free.
 
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tomlib said:
I read on Wikipedia ...
Can you link to the specific page in question? It seems like you may be misremembering the quote.
 
Galileo presumably did an experiment in the late 16th century in which he dropped two objects of different weight from the top of the tower of Pisa and found they reached the ground below at the same time. Unfortunately there is no video of it. However, US astronauts repeated Galileo's experiment on the Moon and made a recording. They dropped a feather and a hammer through the airless space above the surface and verified that Galileo was right when the feather and the hammer hit the ground at the same time.

 
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tomlib said:
If a greater force acts on something, it will most likely move faster. Is my reasoning correct?
What is the relationship between force and acceleration? (Hint: F=ma). So, while the mass influences the force of gravity, it also influences the acceleration. If you write out the force due to gravity, and also the acceleration you will see, the mass "cancels out."

EDIT
tomlib said:
I read on Wikipedia that when a body is in free fall from zero mass

I'm not sure what "... from zero mass" means.
 
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https://cs.wikipedia.org/wiki/Volný_pád

I think zero mass means the zero begin speed. I use translator.

I don't know much about the formula and I don't exactly understand the shortening in the article. The formula and reasoning must be wrong. It is clear that when I say that as force increases, acceleration must also increase. Strength increases with body weight. If I push the car with more force it will move faster. Again, a place is offered here for the description of such a phenomenon, i.e. the necessary initial force,
the fact of measuring speed and force. Free fall could be measured on video, but it is difficult to test it somewhere. It seems to me that a=F*m, where g is substituted for F.
 
tomlib said:
It seems to me that a=F*m, where g is substituted for F.
Not exactly. ##F \neq g##$$F_\text{gravity} = mg$$The force of gravity on an object increases when you increase gravity. It also increases when you give the object more mass.

But we also know that$$\sum F=ma$$If gravity is the only force operating then ##\sum F = F_\text{gravity}##. So$$a = g$$.
 
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At the risk of pointing out the obvious, this is an extremely easy proposition to experiment.

Just drop two reasonably compact items of meaningfully different masses: off a ladder, second floor window, the front porch, whatever. Great accuracy in measurement should not be needed, just make sure that there aren't hurricane force winds present, and that object B is about 3 or 4 times the mass of object A. Repeat several times. Have an assistant near the landing zone to watch the impacts just to be sure.

Should give you all the working data (within a reasonable range of accuracy) that you need.
 
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tomlib said:
Hello. I read on Wikipedia that when a body is in free fall from zero mass, its mass does not matter and two bodies of different weights will fall at the same speed. I think this is not correct. If I consider that the bodies are in a weightless state and the gravitational force will act on them. This force will be as great as the weight of this body.
If a greater force acts on something, it will most likely move faster. Is my reasoning correct?
i think what was said in more technical terms, is that yes, you have more "force" due to a higher weight (which is a force) but the mass is greater, so it cancels out. 9.8Newtons on a 1kg object will accelerate at 9.8meter/sec/sec (acceleration). since acceleration (g) is constant, if increase the mass to 2kg, that will raise the weight of the object to 19.6Newtons, and the acceleration is still 9.8mpsps......... later you can investigate why the object is weightless when it falls, but still accelerates with respect to the ground..... hmmm it seems the ground is accelerating up to the object.... see Einstein and the bending and warping of space time as a cause.
 
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tomlib said:
It is clear that when I say that as force increases, acceleration must also increase.
Yeah, but if you increase the mass by the same ratio as you increase the force, the acceleration will not change.
 
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