Universal Definition and 477 Threads

Space expands. So we are told. But why only intergalactic space? I asked Stephen Hawking once (I happen to live in the same town), and he replied 'gravitationally bound systems (such as the Local Group of galaxies) do not expand'. Why not? Does gravity have a limited range? An expansion...

Complement of Universal Turing Machine - Does this exist?? I am kind of confused in terms of the creation of machine which does NOT (Universal Turing Machine). I mean I construct a TM which will simulate UTM and accept strings it rejects and rejects strings it accepts. So if L(UTM) defined as...

[SOLVED] Universal Gravitation Homework Statement Jupiter's closest moon, Io has a mass of 8.90 x 10^22 kg. The mean radius of Jupiter is 6.99 x 10^7m, the mean distance from the center of Jupiter to the center of Io is 4.22 x 10^8m, and the mass of Jupiter is 1.90 x 10^27. A) Determine...

I heard that at the time of the big bang the universe expanded faster than the speed of light, can anyone back me up on this? and if it is true then does that mean that the speed of light is not the universal speed limit?

Two spheres are released from rest when the distance between their centers is 12R. Sphere 1 has mass M and radii R while sphere 2 has mass 2M and radii 3R. How fast will each sphere be moving when they collide? Assume that the two spheres interact only with each other. (Use G for gravitational...

If the universal gravitational constant was changed from 6.67 X 10^-11 to 6.67 X 10^+11 what would happen? Hi. I am doing a physics project for grade 12 physics. Here is the question: The universal gravitational constant, G, is suddenly changed from 6.67 X 10^-11 Nm^2/kg^2 to 6.67 X 10^+11...

Homework Statement A bowling ball (mass = 7.2 kg, radius = 0.10 m) and a billiard ball (mass = 0.48 kg, radius = 0.028 m) may each be treated as uniform spheres. What is the magnitude of the maximum gravitational force that each can exert on the other? N Homework Equations...

[SIZE="3"]"Distances among galaxies in clusters on average are no greater than their diameter". Luminosity, color, and other qualities are used to obtain distances - and these values are connected to masses that are observed by motions. If a system is in equilibrium then the theorem is...

What exactly is meant by universal law? I have read in a book a that Ohm's law is not a univeral law. I somewhat understood that as Ohm's law is not obeyed by all materials and not always. But I read now in another book that Coulomb's law is also not a universal law. Now I am beginning to...

Homework Statement Determine the magnitude of the force of gravity acting on a 340 kg satellite, 850km above Earth's surface. Homework Equations So I dedcided to use the Universal Gravitation Law: Fg = (Gm1m2)/d^2 The Attempt at a Solution m1=5.98E24 (earth's mass) m2=340kg...

I got injured while playing football and had to miss a Thermodynamics-I lecture. Got the notes afterwards but they tend to make things more complicated. The notes starts with :- Pv=RT Which R is this the Universal Gas Constant or the Individual Gas Constant ? Is the Molar Volume and Specific...

why not free universal healthcare if ... ... the United States military and NASA is funded directly through our taxes? I must admit I am not very knowledgeable of what will happen to the quality of our healthcare system if funding was supported through taxes. I know socialized medicine works...

Homework Statement A synchronous satellite, which always remains above the same point on a planet's wquator, is put in orbit around Jupiter to study the famous red spot. Jupiter rotates once every 9.84 h. find the altitude of the satelite Homework Equations jupiter: mass in kg...

Hi everyone, Could someone please help me on this problem? Homework Statement Newton's law of universal gravitation is represented by the following equation where F is the magnitude of the gravitational force exerted by one small object on another, M and m are the masses of the...

Something has recently occurred to me which I think I should mention here. Boltzmann brains have a definite probability of "popping up" anywhere in the universe as fully formed, sentient beings. Although the odds against such a thing happening are astronomical, there is a probability which can...

Homework Statement The gravitational force between two shperes is 2.50x10^-8. Their centers are 105 cm apart. The larger sphere has a mass of 8.20 kg. Find the mass of the smaller sphere. Homework Equations F=Gm[SIZE="1"]1m[SIZE="1"]2/d² The Attempt at a Solution...

[SOLVED] Universal Gravitation Homework Statement A small rocket is launched vertically, attaining a maximum speed at burnout of 1.0x10^2 m/s and thereafter coasting straight up to a maximum altitude of 1519 m. Assuming the rocket accelerated uniformly while the engine was on, how long did it...

Neutron stars are extremely dense objects that are formed from the remnants of supernova explosions. Many rotate very rapidly. Suppose that the mass of a certain spherical neutron star is twice the mass of the Sun and its radius is 5.0 km. Determine the greatest possible angular speed it can...

[SOLVED] Universal Gravitation Ice Rink Problem! :) never mind

[SOLVED] Universal Gravation Problem --experts needed haha Never Mind.

Homework Statement What does the 3K universal blackbody temperature radiation tell us about the temperature of the outer space? Homework Equations The Attempt at a Solution the 3K universal blackbody radiation is regarded as the remnant of the Big Bang.And this temperature looms all...

Homework Statement A student proposes to measure the gravitational constant G by suspending two spherical objects from the ceiling of a tall cathedral and measuring the deflection of the cables from the vertical. If two 155.0 kg objects are suspended at the lower ends of cables 40.00 m long...

"Consider the Earth following its nearly circular orbit about the sun. The Earth has a mass mearth=5.98x10^24kg and the sun has mass msu=1.99x10^30kg. They are separated, center to center, by r=93 million miles = 150 million km." What is the size of the gravitational force acting on the Earth...

Homework Statement For this problem, use ratios only to obtain the weight of a person at the following distances. Assume the person weighs 980N on the surface of Earth. a) 128 000km above the surface of Earth b) 4.5 times the distance from the centre of Earth c) 745 400km from Earths...

Homework Statement Two tankers of equal mass attract each other with a force of 3.5 x 10(to the power of 3)N. If their centres are 85m apart, what is the mass of each tanker? mass of 2 tankers = ? F= 3.5 x 10(to the power of 3)N r= 85m G = 6.67 x 10(to the power of -11)...

Homework Statement The question is: What is the distance between the moon and the Earth if the mass of the moon is 7.34 x 10(to the power of 22) kg and the force of attraction between the two is 2.00 x 10(to the power of 20) N? Mass of the moon = 7.34 x 10(to the power of 22) kg...

1. The mass of a robot is 5370 kg. This robot weighs 3520 N more on planet A than it does on planet B. Both planets have the same radius of 1.33 x 10^7 m. What is the difference MA - MB in the masses of these planets? 2. attached picture 3. I was wondering what to do with the...

[b]1. The problem statement, U= x:xless than 11, [b]2. Homework Equations ----(A n B')' n C The Attempt at a Solution

*note before reading: pretend that the superscripts are really subscripts, for some reason , Latex is making the subscripts into superscripts* I'm not sure if I'm interpreting the universal coefficient theorem for homology correctly. Let's say I have a Homology group H(X;Z). This is a...

The title might be a little ambiguous since I do not mean to talk about time curvature. I am interested in some non-technical explanation, in some historical context, of past and current knowledge/research (if there ever was) regarding the possibility that the time line might be entirely...

Homework Statement Given: The universal gravitational constant G = 6.67 E-11, the mass of the Earth M = 5.98E24, and its radius R = 6.7 E6. How much work must an external force do on the satellite to move it from a circular orbit of radius 2R to 3R, if its mass is 2000kg? Answer in Joules...

Homework Statement My prof proposed a question for us. He gave us this information: if your body is inside an object (earth) and is located at 10% of the Earth's radius, what is the acceleration? We are currently learning about Newton's law of universal gravitation but I'm not sure I see...

Homework Statement At what height above the Earth's surface is the acceleration due to gravity 10% of that at sea level? Homework Equations F= Gm1m2/r(squared) The Attempt at a Solution I think some how one of the masses is moved over so that F/m=a and I think .10 is multiplied...

OKAY, I AM REALLY AGAINST THE PROOF FOR THE IRRATIONALITY OF THE ROOT OF 2. Is there a proper universal proof for proving irrationality? I mean, my teacher used the same logic for proving irrationality of 3! All I see is that I can show that the square root of 4 or 9 are also irrational...

I was thinking yesterday about the fact that the universe is supposedly expanding at an ever increasing rate and i thought of i reason why. I'm pretty sure its wrong but so far nobody could explain to me why. If you assume that the there is an infinetly big nothingness for our current universe...

Universal statements are not falsifiable. The reason is that they are defined, supported, reliant upon[...] lexicon! Lexicon is not science, but its all about establishing vocal or verbal conventions that are "blurt" whenever referencing some concrete or abstract entity. "All universal...

We all accept that the universe is expanding and that expansion is accelerating. So what exactly are the speeds of those far off galaxies with respect to an Earth observer. And if the universe is destined to continue this expansion forever, then won't the speeds of far off galaxies eventually...

Homework Statement If you threw something vertically upward from the moon's surface where g=1.6N/kg [down], how many times higher would it reach compared to throwing it from the surface of the Earth with the same force? Neglect the effect of air resistance on the Earth. Homework...

From general research, I have seen a certain pattern emerge that causes me to re-evaluate how I look at the universe. It's easier to see with visuals, but I will try to describe it here. I believe some of the abstractions can lead to a better understanding of the structure of the universe, or at...

This question may be a simple one, but the answer will have lots of implications that I'll follow up on. I'm trying to steer clear of all the jargin though since for the most part it's pretty useless. Say there is an object B orbiting an object A of the same size. What happens when an object C...

What are some calculations or ideas that we could use to determin our position in relation to the universe? - btw I did absolutley no research on this matter prior to posting this so ... don't beat me up too much :P

Hi, I'm trying to solve Newton Universal law of Gravitation as a differential equation in one dimension with two objects. One mass is fixed at distance r = 0, whilst the other is some initial distance away. I'm using distance rather than displacement and also ignored the proportionality factor...

im stuck with this problem: the question asked for the gravatational force of attraction between moon and Earth while the moon's radius is not given. do i need the moon's radius? since r is the distance from the center of moon to the center of Earth (right?) and the second question of the same...

If everywhere in the universe is at above 0 degrees Kelvin, then there must be some degree of heat everywhere, so this could be considered a universal medium or not, and if what I heard about the sound of the big bang still reverberating throughout the universe is correct (see my contribution to...

What do you think, is there something in this universe that does not change, no matter who looks upon it or from where? Is the speed of light the constant that it can be claimed to be? If there is no constant, then what are we comparing everything to, for example in chemistry, standard...

Homework Statement mass of star = 2.53 x 1030 kilograms mass of planet = 5.25 x 1024 kilograms mass of moon = 8.09 x 1022 kilograms average distance from star to planet = 1.14 x 1011 meters average distance from planet to moon = 4.59 x 108 meters Use the data above to determine the net...

Most likely a basic question to most, been awhile since I've done any of this. If i remember right the formula states, F = G*M_1*M_2/d^2 where d = distance between M_1 and M_2 Im creating a planetary simulator for fun, i get the initial position of the Earth using the 7 variable Astrological...

The biggest chunk of evidence for expansion of the universe is the whole red-shift/Doppler effect deal, saying that as something that emits light while traveling away from the observer, the wavelength of the light will be "stretched" making it appear red. There is one thing I'm wondering. Could...

When two masses collide, assuming there are no external forces on the system of the two masses, will they collide with the same velocities or will it depend on the conserved momentum? Edit -- Assume they're released from rest, since that's what the problem I'm working on states.

I'm new to the physics forums so correct me if I'm in the wrong place. We started a new unit on universal gravitation in my physics class, and I'm not sure I understand the following passage from the beginning of the chapter: "Albert Einstein made the amazing discovery that gravity arises...