Universal Definition and 488 Threads

Given F is directly proportional to the product of m1 and m2. F is also inversely proportional to the r^2. F, m1, m2 and r are real numbers. Why we can link the above two variations together and say that F=km1m2/r^2, where k is the proportionality constant? Aren't the the variations...

I'm reading a book on category theory and I'm stuck on this problem: For a given abelian group, what is the universal morphism to the forgetful functor Ring->Ab taking each ring to its underlying additive group? I think if the functor was Ring -> Monoid taking each ring to the underlying...

I'm asking this in the classical physics forums, because I view it as basically a thermodynamics question, but I'm wondering if I should put it in either the relativity or astrophysics forum, or even the quantum forum, because this topic is generally talked about in terms of cosmology...

As I have understood from reading about special relativity there is NO absolute time, NO universal time, ONLY local time. I have two questions: 1) The same transformations apply to space. Is it then reasonable to conclude that there is NO absolute space, NO universal space, ONLY local space...

could the universe act like a wave that at the present time is accelerating towards a peak something akin to an electromagnetic sine wave? And once the peak is reached it starts to deflate? Could this dark energy be the alternate wave that is at right angled to the universal wave? Just musing...

Disclaimer: I am a science buff – not a scientist. I am curious to know if there has ever been a theory developed about the infinite nature of the universe, large and small, relating to a fractal structure. I was pondering fractal subdivision, and how it offers at least the theoretical...

I'm not a physics major or anything (I'm actually a biochem major) but I was just wondering if the universal background radiation that keeps the universe (on average) a few degrees Kelvin warmer than absolute zero could possibly be enough to generate electricity. Essentially this minuscule...

Homework Statement Transplanertay tours promises tour participants a certificate to commemorate their passage from the stronger influence of Earth's graviational pull to the stronger pull of the Moon at the point where the two forces on your spaceship are equal. Where on the trip should you...

Homework Statement During a solar eclipse, the Moon, the Earth, and the Sun all lie on the same line, with the Moon between the Earth and the Sun. (a) What force is exerted by the sun on the moon? (b) What force is exerted by the Earth on the Moon? (c) What force is exerted by the sun on the...

If a little knowledge is a confusing thing, I certainly have the prerequisites to be confused about Universal Expansion. Some physicists seem to be saying that all the stars and galaxies are flying apart like shrapnel from a large explosion, and other physicists seem to be saying that space...

Homework Statement A satellite of mass 4600 kg orbits the Earth (mass = 6.0 1024 kg) and has a period of 5500 s. (a) Find the magnitude of the Earth's gravitational force on the satellite. (b) Find the altitude of the satelite Homework Equations Kepler's Equation: R^3/T^2 Fg=...

What are the universal forces made of? From what I understand, these forces are simply invisible and are yet physical at the same time, how can that be? How can something that has a physical force be made of... nothing? Gravity for example is speculated to be made of gravitons, but it is (at...

Homework Statement What force does Earth exert on a 80.0-kg astronaut at an altitude equivalent to 2.5 times Earth's radius? Homework Equations FG = (Gm1m2) / r2 Radius of Earth: 6370 km Mass of Earth: 5.97x1024 kg The Attempt at a Solution FG = (Gm1m2) / r2 FG = (G x MEarth x 80...

Homework Statement Three 6 kg masses are located at points in the xy plane as shown. r1=47 cm r2=55 cm What is the magnitude of the resultant force (caused by the other two masses) on the mass at the origin? The universal gravita- tional constant is 6.6726 × 10^−11 N · m2/kg2. Answer...

First off this is not homework or coursework, just general interest. I've been looking to derive the rocket equation which includes the effects of Universal Gravitation. I've been able to derive it assuming near Earth gravity where g is taking as constant acceleration...

One popular and credible theory on the overall shape of the universe is the positively curved universe. In my mind that is the 3-sphere which is connected and finite sort of like in the balloon analogy. And the following discussion regards such a universe I think. As I understand the regular...

What is the difference between the time scales of Greenwich Mean Timt, GMT and Universal Coodinated Time, UT? I know it ticks with TAI but is 34 seconds off due to leap seconds keeping the UT1-UTC ratio below 0.9 due to the slowing of the Earth's rotation.

3 10 kg spheres are located at the corners of a equilateral triangle of sides .5m. Calculate the magnitude of the total gravitational force exerted on one sphere by the other two. I used G = 6.67 x 10^-11. The answer I got was 4.62 x 10 ^-8. Can anyone confirm if this is correct, or explain how...

I apologize for my English, it's not my native language. Homework Statement There's three masses of 1 kg each set in an equilateral triangle of side length 0.8 meters. Mass m1 is located in coordinates (-0.4m, 0) and m2 is located in coordinates (0.4m, 0). What are the coordinates of m3? A...

Privacy policies need more consistency. We have already seen that sites will respond to user demands if they are concentrated and focused, thus it's time for a Social Networks Bill of...

Homework Statement I am doing a lab-"Kepler's Laws and Newton's Law of Universal Gravitation". There is an image representing various positions, at equal intervals, of a satelitte in an elliptical orbit around the earth. A list of planets and their radi and periods are given. I have calculated...

1. Take the equation F=[G(m1)(m2)]/r2 2. Assume a single mass of 20 (units don't matter), which will be divided in the following ways: 2.1. System 1: m1=20, m2=0 2.2. System 2: m1=19, m2=1 2.3. System 3: m1=18, m2=2 2.4. System 4: m1=17, m2=3 . . . 2.11.System 11: m1=10, m2=10 Now... 3...

Homework Statement The average distance separating Earth and the moon is 384000km. What is the net gravitational force exerted by Earth and the moon on a 3.00 x 10^4kg spaceship located halfway between them. Homework Equations F=Gm1m2/r^2 G = 6.673x10^-11 earth mass = 5.98x10^24...

Dont want to read all of this, then just read the last paragraph. If you still mixed up then read all of it. Why does einsteins theory of general relativity deal with c, the speed of light in a vacuum, the speed of light can take on many different forms when traveling through mass. But...

Homework Statement At a certain point between Earth and the Moon, the net gravitational force exerted on an object by the Earth and the Moon is ZERO. The mass of the Moon is 1.2% the Mass of the Earth. The centre to centre distance between the Moon and the Earth is 3.84*10^5 km. i) WHERE IS...

I think I understand the basics of the Big Bang but after trying to explain it to someone else, I've discovered that there are many details lacking in my knowledge. So I have come here in the hopes of alleviating my ignorance... I understand that in the very early universe, all the energy in...

I’d like to know if anyone has heard of anything along the lines in this article (abstract and link are below) before - that gravitational atractive motion sort of fades into universal expansive motion as distance increases…and how that relates to Chernin's concept of a “zero gravity shell”...

Homework Statement Two objects attract each other with a gravitational magnitude 1.00x10-8N when separated by 20.0cm. If the total mass of the two objects is 5.00kg what is the mass of each? Homework Equations Fg=G*m1m2/r2 G=6.673x10-11Nm2/kg2 I'm not real sure how to go about this...

Hi Guys I am in year 12 and have my exam shortly would just like to ask a question to do with gravity. A small satellite orbits Mars. It has a kinetic energy of 3.0x10^10 J, and is at a constant distance of 8.0x10^7 m from the center of Mars. What is the weight of the satellite at this height?

Does there exist a database with very specific mathematical definitions, theorems... etc? I've found that some thm's/dfn etc differ from author to author. Not necessarily in meaning, but in the words used to describe them. Is there a place where a precise definition can be found that is agreed...

Wherever I have read, the conservation of momentum is a universal truth. This is the basis, as I undertsand it, to the mass equation: m = m0/SQRT(1 - v2/c2) in which m0 = the mass in the rest frame and m is the mass in the moving frame relative to the rest frame moving at v. The idea...

If someone is willing to briefly explain what these three branches of mathematics are about, I'd appreciate it. I don't even understand if they are three completely different things or if they're overlapping a lot. I understand the definition of a category, and Landau just made me aware of the...

Homework Statement A small package is fired off Earth's surface with an unknown launch speed, but with a known launch angle of 51.0 as measured from the local horizontal. It reaches a maximum height above the surface of 6380.0 km, a value equal to Earth's radius itself. What is its speed when...

Homework Statement Very far from Earth (r = infinity), a spacecraft has run out of fuel and its kinetic energy is zero. If only the gravitational force of the Earth were to act on it (i.e., neglect the forces from the sun and other solar system objects), the spacecraft would eventually...

Using F = G * (m1*m2)/(r2) We know that G = 6.6673x10-11 N*m2/kg2 m1(earth) = 6x1024 kg m2(moon) = 7.4x1022 kg the Earth and moon are an average of 3.9x108m apart would r2 be [3.9x108]2 or [3.9x108 / 2]2? -Thanks!

Water Waves -- Universal Wave Equation Homework Statement Attached. Homework Equations v=fλ The Attempt at a Solution f= cycles/time f= 45/60 f= 0.75 Hz The trouble I am having is wondering if λ is 28 m or do i have to do something else to find λ?

Hey If you have the Minkowski line equation of -ds^2 = c^2 d tau^2 = c^2 dt^2 - dx^2 - dy^2 - dz^2 I don't understand how you can assume from this ^ that each observer in different reference frames will experience time changing at the same rate 'dt'. I thought that tau was the relative...

I understand that in a uniformly expanding universe of the Einstein-de Sitter type, the distances between galaxies is constantly increasing but that the red shift displayed by those galaxies is not due to the Doppler shift - rather it is due to the fact that, during the time it takes for their...

I have read theories that space itself is expanding, but if this were the case wouldn't our perception of this expansion be skewed by the very fact that we ourselves are part of the expansion? Has anyone pursued a theory that what we hold as constants, the power of the weak force, the power...

Newton's universal law of gravitation states that every bodies in this universe attracts each other.Was Newton able to explain the reason for this attraction?

"Mathematics is the only Subject that can Provide Universal Truths" "Mathematics is the only subject that can provide complete and utter universal truths, whereas no other subject can." Is this statement true? Trying to win a science vs religion argument with a friend. I have constantly...

Derivation of Newton's law of universal gravitation... Non-relativistic Schwarzschild metric: c^2 {d \tau}^{2} = e^{\nu} c^2 dt^2 - e^{\lambda} dr^2 - r^2 d\theta^2 - r^2 \sin^2 \theta d\phi^2 metric identity: g_{00} = e^{\nu} c^2 = \frac{ds^2}{dt^2} Non-relativistic Einstein tensor: G_{11} =...

The height of a mountain is limited by the ability of the atoms at the bottom to sustain the weight of the materials above them. Assuming that the tallest mountains on Earth (at about 8850m) are near this limit, how tall could that mountain be on Mars, with mass .11Me and radius .53 Re? I...

Hello all, 1) Does the universal gravitation law apply to every two particles in the universe, no matter how far they are from each other? For instance, is there a gravitation force between the pen in my hand and the farthest particle(or star) in the universe, I don't care how small this force...

A distant star has a single plante orbiting at a radius of 3.51X10^11m. The period of the planet's motion around the star is 853 days. What is the mass of the star? The universal gravitational constant is 6.67259X10^-11N m^2/kg^2. Answer in kg. Alrighty. So I tried to find the mass by using...

Ok, well my Honors Physics teacher doesn't really like to "teach" but rather give us a list of equations, and then throw a packet at us and tells us to do it. Last semester I got a C and I know that I could do much better if I was actually explained the information and how and when to apply the...

K, so I don't quite understand how I find a persons weight on a different planet using the said person's weight, the mass of the other planet, and the radius of the planet? So, for example: Max weighs 1000 N on Earth. What would his weight be on a planet with twice the mass of Earth, but...

20. According to Newton’s law of universal gravitation, the force of attraction between any two masses is related directly to the A. velocity of the two masses B. product of the two masses C. distance between the masses D. sum of the masses ( I wasnt sure for this question so I had to...

Humans today are in a race for their very survival. It is essential that each generation work towards it's full potential as to aid the development of space travel and colonization. It's in our DNA, our primary function is to survive. So at some point that will become the absolute...

Homework Statement Certain neutron stars (extremely dense stars) are believed to be rotating at about 6 rev/s. If such a star has a radius of 15 km, what must be its minimum mass so that material on its surface remains in place during the rapid rotation? G=6.67*10-11m3 kg-1 s-2 Homework...