Law of Attraction Warning !

Our galaxy, the Milky Way, contains approximately 4.02×10^11 stars with an average mass of 2.49×10^30 kg each. If the Andromeda Galaxy, our nearest neighbor, contains roughly the same number of stars and is 2.26×10^43 meters away, what is the gravitational force of attraction between the two galaxies?

I used the Law of Universal Gravitation.. but i’m getting different numbers everytime i punch them into my calculator.. please help?

Thanks!!

Assuming the average mass of stars in Andromeda is the same as the Milky Way
F = G(nm)^2R^2
F = 6.673 x 10^-11 x (4.02 x 10^11 x 2.49 x 10^30)^2/(2.26 x 10^43)^2 = 1.30 x 10^-13 N

Newton’s law of universal gravitation states that every particle in the Universe attracts every other particle. Write the exact mathematical expression for the force of attraction, and state in few words why this force of attraction is stronger between the moon and the earth than it is between you and your friend?
Thank you for answering my question! It made sense to me.

F = G (m1 . m2)/r^2

Since ‘G’ value is constant, I guess the reason here is my friend and I don’t have huge masses unlike moon and earth.

The hydrogen atom contains a proton and an electron seperated by about 5.0 x 10(-11) m. (the (-11) is supposed to be to the -11 power.)The mass of a proton is approx 1.7 x 10(-27) kg. (the (-27) means to the power of -27 also.) The mass of the electron is approx 9.0 x 10(-31)kg. (same thing as before(to the power)) The charge on a proton is 1.6 x 10(-19)C (same thing as before) and the charge on an electron is -1.6 x 10(-19) C.
Newton’s law of universal gravitation:
F(g)=(6.67 x 10(-11)power) x m1 x m2
(all this equation divided by r(2) (r squared)
Coulombs law:
F(e)=(9 x 10 (9) power) x q1 x q2
(all this equation divided by r(2) (r squared)
a) Use newtons law of universal gravitation to calculate the gravitational force between the electron and proton in the hydrogen atom.
b)Use Coulombs law to determine the force of attraction between the 2 particles.
c)Calculate the ratio between the electric force and the gravitational force. How import. are gravit. forces in this case?

Come on now this is a common sample problem to show you how the Coulomb force is so much LARGER than the gravitational force. You should do it yourself. It’s a matter a plugging in the Numbers in Coulomb’s Eq and then into Newton’s and forming a ratio.

It will show you that Gravitational forces are unimportant when calculation electrical forces between charged particles.

Consider 2 ordinary objects of mass 1 kg each and seperated by a distance of 1 meter. calculate the force between them using newtons universal law of gravitation. now consider 2 magnets of the same mass (1kg each) and seperated by the same distance (1 meter). now calculate the force between them.. theoretically these 2 forces must be equal but practically they are not coz the magnets themselves have have their own magnetic force of attraction. can u tell why?? does the law hold good for magnets??

They are not equal. They variates both over the inverted squared distance, but the gravitational force is F=(m1*m2)/μ*r^2 (F is force, m is pole strength, μ is the permeability of the intervening medium, r is the separation) and the gravitational force is F= -G*(m1*m2)/r^2 (G is the gravitational constant, m1 is the mass of the first object, m2 is the mass of the second object, r is the distance between objects). Indeed, those two forces have similarities in the formula, but they are distinct.

Here is where i guessed .the numbers are the words i guessed. correct me if i got it wrong: According to the law of gravitation, all matter 1.pulls on all other objects. You won’t notice the 2. Attraction between you and your pen because 3. Mass is 4. Unbalanced for small objects. Without the resistance from air, all objects fall with the same 5. Acceleration, due to gravity. The force of gravity acts 6. Downward while the 7. normal force acts 8. Upward. When you stand on level ground, the normal force is equal to your 9. Weight. You do not accelerate because the forces acting on you are 10. balanced. Before you start moving, your 11. Inertia must be overcome.
That’s 11 questions i had to figure out. Please correct me if any of these are incorrect. thanks

Those all look fine except number 4 is probably wrong. Here are suggestions to consider.

1 exerts a force of attraction
2 force
3 attraction
4 insignificant

I am tired and did science almost a year ago, so get a second opinion from someone else.