who formulated the Law of Universal Gravitation?

Answer 1

Nicole has it right, Sir Isaac Newton first formulated the Law of Universal Gravitation, f = G*m1*m2/d².

I was not even going to answer this one until I saw y4km0 ts's answer.

Einstein did not develop a law call e=mc2. That formula (actually e=mc² or e=mc^2) was derived from the Lorentz-FitzGerald formulas in his general theory of relativity.

Now, in his special theory of relativity he dealt with gravity and redefined Newton's laws so they match observable fact (particulary the orbit of Mercury, which was a bit off by Newton's Law).

I could write a book in this (in fact many have), but his is not the place for it.

Give Nicole the 10 points, she is correct.

PS: I forgot to add that most astronomers use Newton's Law because it is much simpler to use then Einstein's and the error is very small.

Answer 2

The law of gravitation was first formulated by Isaac Newton in 1684.

Answer 3

law of universal gravitation is formulated by Issac Newton

Answer 4

it was newton who formed the first laws of gravitation, but it was einstein, who perfected tose laws. not perfected rather turned them upside down, rather he bounced off Newton. Einsten found that Newton's laws do not work with heavenly bodies, (by heavnely please dont assume the sipirts of Adam and Eve), so he found a univesal law called E=mc2, which will worrk throughout the space. The bewildering thing about gravitation is that even einsten's laws do not work for micro particles, that is atoms do not behave as stars and planets behave. For that we have another theory called Quantam theory, and mind it, the biggest thoery of all is still waiting to be fomulated, the theory of everything, whcih hold good both for macro and micro particles. Mabye I will be the one who will fomulate it, but before that I will have to learn how to tell time by redaing it from the clock

Answer 5

Sir Isaac Newton. This, along with his Laws of Motion, is one of the pillars of Classical Physics, and it provides a useful first approximation. Of course Einstein "fine tuned" it into a more correct paradigm.

Answer 6

Kepler, Newton, Einstein

Answer 7

Isaac Newton.

Answer 8

Isaac Newton compared the acceleration of the moon to the acceleration of objects on earth. Believing that gravitational forces were responsible for each, Newton was able to draw an important conclusion about the dependence of gravity upon distance. This comparison led him to conclude that the force of gravitational attraction between the Earth and other objects is inversely proportional to the distance separating the earth's center from the object's center. But distance is not the only variable effecting the magnitude of a gravitational force. In accord with Newton's famous equation

Fnet = m*a
Newton knew that the force which caused the apple's acceleration (gravity) must be dependent upon the mass of the apple. And since the force acting to cause the apple's downward acceleration also causes the earth's upward acceleration (Newton's third law), that force must also depend upon the mass of the earth. So for Newton, the force of gravity acting between the earth and any other object is directly proportional to the mass of the earth, directly proportional to the mass of the object, and inversely proportional to the square of the distance which separates the centers of the earth and the object.

But Newton's law of universal gravitation extends gravity beyond earth. Newton's law of universal gravitation is about the universality of gravity. Newton's place in the Gravity Hall of Fame is not due to his discovery of gravity, but rather due to his discovery that gravitation is universal. ALL objects attract each other with a force of gravitational attraction. This force of gravitational attraction is directly dependent upon the masses of both objects and inversely proportional to the square of the distance which separates their centers. Newton's conclusion about the magnitude of gravitational forces is summarized symbolically as


Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases. If the mass of one of the objects is doubled, then the force of gravity between them is doubled; if the mass of one of the objects is tripled, then the force of gravity between them is tripled; if the mass of both of the objects is doubled, then the force of gravity between them is quadrupled; and so on.

Since gravitational force is inversely proportional to the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces. So as two objects are separated from each other, the force of gravitational attraction between them also decreases. If the separation distance between two objects is doubled (increased by a factor of 2), then the force of gravitational attraction is decreased by a factor of 4 (2 raised to the second power). If the separation distance between any two objects is tripled (increased by a factor of 3), then the force of gravitational attraction is decreased by a factor of 9 (3 raised to the second power).

The proportionalities expressed by Newton's universal law of gravitation is represented graphically by the following illustration. Observe how the force of gravity is directly proportional to the product of the two masses and inversely proportional to the square of the distance of separation.




Another means of representing the proportionalities is to express the relationships in the form of an equation using a constant of proportionality. This equation is shown below.


The constant of proportionality (G) in the above equation is known as the universal gravitation constant. The precise value of G was determined experimentally by Henry Cavendish in the century after Newton's death. (This experiment will be discussed later in Lesson 3.) The value of G is found to be

G = 6.67 x 10-11 N m2/kg2
The units on G may seem rather odd; nonetheless they are sensible. When the units on G are substituted into the equation above and multiplied by m1*m2 units and divided by d2 units, the result will be Newtons - the unit of force.



Knowing the value of G allows us to calculate the force of gravitational attraction between any two objects of known mass and known separation distance. As a first example, consider the following problem.

Sample Problem #1
Determine the force of gravitational attraction between the earth (m = 5.98 x 1024 kg) and a 70-kg physics student if the student is standing at sea level, a distance of 6.37 x 106 m from earth's center.


The solution of the problem involves substituting known values of G (6.67 x 10-11 N m2/kg2), m1 (5.98 x 1024 kg ), m2 (70 kg) and d (6.37 x 106 m) into the universal gravitation equation and solving for Fgrav. The solution is as follows:




Sample Problem #2
Determine the force of gravitational attraction between the earth (m = 5.98 x 1024 kg) and a 70-kg physics student if the student is in an airplane at 40000 feet above earth's surface. This would place the student a distance of 6.38 x 106 m from earth's center.


The solution of the problem involves substituting known values of G (6.67 x 10-11 N m2/kg2), m1 (5.98 x 1024 kg ), m2 (70 kg) and d (6.38 x 106 m) into the universal gravitation equation and solving for Fgrav. The solution is as follows:




Two general conceptual comments can be made about the results of the two sample calculations above. First, observe that the force of gravity acting upon the student (a.k.a. the student's weight) is less on an airplane at 40 000 feet than at sea level. This illustrates the inverse relationship between separation distance and the force of gravity (or in this case, the weight of the student). The student weighs less at the higher altitude. However, a mere change of 40 000 feet further from the center of the Earth is virtually negligible. This altitude change altered the student's weight changed by 3 N which is less than 1% of the original weight. A distance of 40 000 feet (from the earth's surface to a high altitude airplane) is not very far when compared to a distance of 6.37 x 106 m (equivalent to approximately 21 000 000 feet from the center of the earth to the surface of the earth); this alteration of distance is like a drop in a bucket. As shown in the diagram below, distance of separation becomes much more influential when a significant variation is made.




The second conceptual comment to be made about the above sample calculations is that the use of Newton's universal gravitation equation to calculate the force of gravity (or weight) yields the same result as when calculating it using the equation presented in Unit 2:

Fgrav = m*g = (70 kg)*(9.8 m/s2) = 686 N
Both equations accomplish the same result because (as we will study later in Lesson 3) the value of g is equivalent to the ratio of (G*Mearth)/(Rearth)2.

Gravitational interactions do not simply exist between the earth and other objects; and not simply between the sun and other planets; gravitational interactions exist between all objects with an intensity which is directly proportional to the product of their masses. So as you sit in your seat in the physics classroom, you are gravitationally attracted to your lab partner, to the desk you are working at, and even to your physics book. Newton's revolutionary idea was that gravity is universal - ALL objects attract in proportion to the product of their masses. Of course, most gravitational forces are so minimal to be noticed. Gravitational forces only are recognizable as the masses of objects become large. To illustrate this, use Newton's universal gravitation equation to calculate the force of gravity between the following familiar objects. Use the pop-up menu to check answers.


Mass of Object 1
(kg)
Mass of Object 2

(kg)
Separation Distance

(m)
Force of Gravity

(N)

a.
Football Player
100 kg
Earth

5.98 x1024 kg
6.37 x 106 m

(on surface)

Answer983 N

b.
Ballerina
40 kg
Earth

5.98 x1024 kg
6.37 x 106 m

(on surface)

Answer393 N

c.
Physics Student

70 kg
Earth

5.98 x1024 kg
6.60 x 106 m

(low-height orbit)

Answer688 N

d.
Physics Student
70 kg
Physics Student

70 kg
1 m

Answer3.27 E-7 N

e.
Physics Student
70 kg
Physics Student

70 kg
0.2 m

Answer8.17 E-6 N

f.
Physics Student
70 kg
Physics Book

1 kg
1 m

Answer4.67 E-7 N

g. Physics Student
70 kg
Moon
7.34 x 1022 kg
1.71 x 106 m
(on surface)
Answer117 N
h. Physics Student
70 kg
Jupiter
1.901 x 1027 kg
6.98 x 107 m
(on surface)
Answer1822 N




Today, Newton's law of universal gravitation is a widely accepted theory. It guides the efforts of scientists in their study of planetary orbits. Knowing that all objects exert gravitational influences on each other, the small perturbations in a planet's elliptical motion can be easily explained. As the planet Jupiter approaches the planet Saturn in its orbit, it tends to deviate from its otherwise smooth path; this deviation, or perturbation, is easily explained when considering the effect of the gravitational pull of Saturn upon Jupiter. Newton's comparison of the acceleration of the apple to that of the moon led to a surprisingly simple conclusion about the nature of gravity which is woven into the entire universe. All objects attract each other with a force which is directly proportional to the product of their masses and inversely proportional to their distance of separation.