Simplicity of the equation F=mg

  • Thread starter FUNKER
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In summary, the conversation discusses the equation F=mg and whether more mass results in less gravity. It is explained that F/m=g does not mean more mass leads to less gravity, but rather that the force varies with the mass. The concept is clarified and the conversation ends with gratitude for the explanation.
  • #1
FUNKER
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ok this may seem stupid to the experienced but it has bothered me for a while.
the Equation F=mg
is it not true that the more mass u have the greater the graviety u have?
and if this is true why then when the equation is rearranged
F/m=g therefore the greater mass you have the less Graviety u have?!
C'mon people the sky is falling the sky is falling

Peace
 
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  • #2
No, F/m=g doesn't say more mass->less gravity, it says given the force on a mass in a gravitational field and the amount of mass, there is so much acceleration. Given:
F=mg
then it should be obvious that:
F/m=(mg)/m=(m/m)g=(1)g=g
The problem in your reasoning is that you make the assumption that the force is constant as the mass increases, and this leads you to the contradictary conclusion. As shown above, the force varies with the mass, so that the answer will always be the same in a given gravitational field where the test mass is small enough not to cause any consequential movement in the tested mass (Earth).
However, if your assumption was right, and the force on a mass was constant and independent of the amount of mass, then g would vary inversly with the size of the mass, which means that greater masses would fall slower. But they don't, so it's not.
 
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  • #3
thanks for clearing that up that makes logical sense and you have solved an ongoing saga for me
I guess the sky isn't falling[b(]
it was like i was the first one out the boat on D-Day
i got Binked
thanks
regards
 
  • #4
I don't know what 'binked' means, and for future reference, something like this should be in the general physics forum.
 

1. What does the equation F=mg represent?

The equation F=mg represents the relationship between force, mass, and acceleration due to gravity. It is known as the equation of motion for objects in a constant gravitational field.

2. How is F=mg derived?

F=mg is derived from Newton's Second Law of Motion, which states that the net force acting on an object is equal to its mass multiplied by its acceleration. In this case, the acceleration is due to gravity and is denoted by 'g'.

3. What are the units of measurement for each variable in F=mg?

The force (F) is measured in Newtons (N), mass (m) is measured in kilograms (kg), and acceleration due to gravity (g) is measured in meters per second squared (m/s^2).

4. Can F=mg be used for any object?

Yes, F=mg can be used for any object in a constant gravitational field, regardless of its shape or size. However, it may not be accurate for objects in non-uniform gravitational fields or in situations where other external forces are present.

5. How does F=mg relate to weight?

F=mg is often used to calculate an object's weight, as weight is the force of gravity acting on an object and is equal to the mass of the object multiplied by the acceleration due to gravity. Thus, weight can be calculated by using the equation W=mg, where W represents weight.

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