Gravity Questions: Explaining Why Mass Doesn't Matter When Free Falling

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In summary, the conversation discusses the relationship between mass and gravity, particularly in the context of Galileo's experiment and the equations F=ma and F=\frac {Gm_1m_2}{D^2}. The summary points out that the assumptions made about the distance D and the mass of the Earth are important in understanding this relationship.
  • #1
misogynisticfeminist
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I was wondering something about gravity and I think someone has posted this before here but i think the thread is gone. Galileo's experiment showed that everything falls onto the Earth at equal acceleration.

So, i messed around and, say if I equate [tex] F=ma [/tex] with [tex] F=\frac {Gm_1m_2}{D^2} [/tex], the masses actually cancel out. Is this the right way to do it? and to explain why the mass of an object doesn't matter when free falling on the Earth's gravitational field?

but also if we take [tex] m_1 [/tex] as the mass of the particular object, would [tex] m_2 [/tex] be the mass of the Earth? If so, i would get, [tex] m_2 = \frac {g{D^2}}{G} [/tex]. Since the mass of the Earth is constant, then where does D come in here?

Or is my way of doing this totally wrong ? !

Thanks..
 
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  • #2
misogynisticfeminist said:
I was wondering something about gravity and I think someone has posted this before here but i think the thread is gone. Galileo's experiment showed that everything falls onto the Earth at equal acceleration.

So, i messed around and, say if I equate [tex] F=ma [/tex] with [tex] F=\frac {Gm_1m_2}{D^2} [/tex], the masses actually cancel out. Is this the right way to do it? and to explain why the mass of an object doesn't matter when free falling on the Earth's gravitational field?

but also if we take [tex] m_1 [/tex] as the mass of the particular object, would [tex] m_2 [/tex] be the mass of the Earth? If so, i would get, [tex] m_2 = \frac {g{D^2}}{G} [/tex]. Since the mass of the Earth is constant, then where does D come in here?

Or is my way of doing this totally wrong ? !

Thanks..

Nothing you're doing is wrong,just the assumption that D is anything different that Earth's mean radius...or the distance between Earth's center and the object itself...
So,yes,Earth's mass is equal with the product between gravitational acceleration and Earths's mean radius squared devided by Cavensdishs' constant,as long as the object is assumed at the Earths'surface and Earth a spherical body...
 
  • #3


Your approach to equating F=ma with F=\frac {Gm_1m_2}{D^2} is correct. This equation, known as Newton's law of universal gravitation, states that the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

In the case of free falling, the only force acting on the object is gravity. This means that the acceleration of the object is solely determined by the gravitational force, which is dependent on the mass of the object and the mass of the Earth. However, as you correctly pointed out, the mass of the Earth is constant and the distance between the object and the Earth's center (D) is also constant. This means that the acceleration of the object will be the same, regardless of its mass.

To understand this concept further, we can look at the equation for acceleration, a=\frac {F}{m}. Since the gravitational force (F) is constant, the acceleration (a) will also be constant. This means that objects of different masses will experience the same acceleration due to gravity when free falling.

In summary, the mass of an object does not affect its acceleration when free falling because the gravitational force is dependent on both the object's mass and the Earth's mass, but the other factors such as distance and the gravitational constant (G) remain constant. This is why Galileo's experiment showed that all objects fall at the same rate, regardless of their mass.
 

FAQ: Gravity Questions: Explaining Why Mass Doesn't Matter When Free Falling

What is gravity and how does it work?

Gravity is a force of attraction between two objects that have mass. It is one of the four fundamental forces in the universe and is responsible for keeping the planets in orbit around the sun and objects on Earth from floating off into space.

Why does mass not matter when falling?

Mass does not matter when falling because gravity affects all objects equally, regardless of their mass. This means that a feather and a bowling ball will fall at the same rate in a vacuum, despite their difference in mass.

How does gravity affect free falling objects?

Gravity causes free falling objects to accelerate towards the Earth at a rate of 9.8 meters per second squared. This acceleration is constant and does not change, regardless of the object's mass.

What is the difference between weight and mass in relation to gravity?

Weight is a measure of the force of gravity on an object, while mass is a measure of the amount of matter in an object. Weight can change depending on the strength of the gravitational force, but mass remains constant.

How does gravity work on different planets?

Gravity works the same way on all planets, but the strength of the gravitational force varies depending on the mass and size of the planet. This is why objects weigh less on the moon, which has less mass and a weaker gravitational force compared to Earth.

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