Universal gravitation Definition and 148 Threads

Homework Statement The moon has a mass of approximately 7.34x1022kg and a radius of about 1785 km. Determine the strength of the gravitational field on or near the surface of the moon. Homework Equations I have made a list of equations that are relevant for this entire module on...

Homework Statement Neptune is about 17.2 times the mass of Earth. Satellite N orbits Neptune with the same orbital radius as satellite E that orbits the Earth. Determine which satellite has the smaller period. Support your answer with appropriate calculations. Homework Equations I have...

Homework Statement An astronaut weighs 833N on the surface of the Earth. Determine the weight of the astronaut on Planet Z if the planet's mass is 50.0 times the mass of the Earth and has a radius of 10.0 times the radius of the Earth. Homework Equations Kepler's 3rd law...

Homework Statement The moon orbits the Earth at a distance of 3.84x108m from the centre of Earth. The moon has a period of about 27.3 days. From these values, determine the mass of the Earth. Homework Equations Kepler's 3rd law: (Ta/Tb)2=(Ra/Rb)3 motion of planets must conform to...

Homework Statement Two satellites are orbiting around the Earth. One satellite has a period of 1.5 h and is 250 km above the Earth's surface. The second satellite has a period of 7.5 h. Using Kepler's Laws and the fact that the Earth's radius is 6.38x106 m determine the height of the second...

Homework Statement The Earth has a mass of 5.98x10^24 kg and the moon has a mass of 7.35x10^22 kg. The distance from the centre of the moon to the centre of the Earth is 3.84x10^8 m. A rocket with a total mass of 1200 kg is 3.0x10^8 m from the centre of the Earth and directly in between Earth...

Homework Statement is there a point between the Earth and the moon for which the net gravitational force on an object is zero? Where is this point located? Note that the mass of the Earth is 5.98x10^24 kg, the mass of the moon is 7.35x10^22kg, and the distance between the centres of Earth...

Homework Statement A space vehicle of mass 555kg, experiences a gravitational pull from Earth of 255N. The mass of Earth is 5.98x10 (to the power of 24) kg.How far is the vehicle a) from the center of the Earth, and b) above the surface of the Earth? Homework Equations FG = GM1M2/d squaredThe...

Can anyone tell me that why we take r square instead of r?

Homework Statement what is the magnitude of Gravitational force for the following picture(s) (attached to forum) Homework Equations Fg = G M*M/D^2 The Attempt at a Solution I tried to do some of them I know the equation for the second one is fG = 2G M*M/D^2 and for the third one...

High guys, I've always had problems with this law at the way it was explained.But now I've seen lewin explaining that way that bothers me: In terms of sensations.At 1:50 http://youtu.be/M_8w-dD4RBE What I think is that we "feel" the pull only because we are made of multiple particles...

Hello, i am so confused Newton's universal gravitation states FG= Gm1m2/r squared and in this case FG stands for the force of gravitational attraction between any 2 objects, but why is Fg (gravitational field strength) equaled to fg=Gm/r squared? why are FG and Fg used interchangeably? i do not...

1) Graph Fg vs. r Fg on y-axis, r on x-axis (from 1re to 6re) re (radius of the Earth) 2) If a cannon ball is fired from the top of Everest parallel to the Earth's surface fast enough (ignoring air resistance and assuming that it doesn't bump into anything), it will "orbit" the Earth and...

Homework Statement Answers: 56. 6.16 x 10^17 N, 57. 894 N Homework Equations Fg = G*m1*m2/r^2 g = G*M/r^2 The Attempt at a Solution 56. Since the closest planet to Z is Y I figured the gravitational force could be calculated by just finding the gravitational force between Z and Y...

What is the Relationship between Kepler's law and universal gravitation law? (IT HAS SOMETHING TO DO WITH THE CENTRE OF MASS)I know this; Newton's Law of Universal Gravitation F=mGM/r^2 derived Keplers Third Law r^3/t^2= constant: mGM/r^2 = mv^2/r gives GM/ (2pi)^2 = r^3/t^2. Read more...

I'm having trouble with part a) of this question... [PLAIN]http://img69.imageshack.us/img69/5815/98157006.png So I started off by solving the DE above a), and I've gotten it down to: \frac{1}{2} m v^{2} = \frac{mgR^{2}}{(x + R)} + C I can tell I'm getting close, but I'm a little...

We just started on a chapter about gravity in my physics class. I'm curious about this: If two rings of different radius and masses of, say, 3 kg and 2 kg, are placed inside each other so that their centers of mass are extremely close (i.e. 1.0 x 10^-9 m) together, would the gravitational force...

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...

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...

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=...

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...

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...

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...

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...

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...

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?

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!

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...

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...

Homework Statement Given: G = 6.67259 × 10^−11 Nm2/kg2 A small Moon of a planet has an orbital period of 2.08 days and an orbital radius of 5.04 × 10^5 km. From these data, determine the mass of the planet. Answer in units of kg. Homework Equations FG=FC FG=Gm1m2/r^2 FC=mv^2/r The...

Update: Thanks for the help! I'll work on it...

I'm trying to understand the basics of gravity. Newtons law of universal gravitation gives us : F1 = F2 = G (m1m2)/r2 Now on Earth you can simply that down to F = mg where g = G (mearth/R2) But using f = mg, a heavier object say a tennis ball should fall faster than a cannon ball. But...

hello, I'm not saying that Newton's law of universal gravitation is really wrong but there are phenomenons which i don't think the law is really correct and i want someone to help me. There might be explanations but i don't really know any explanations right now so an explanation would be...

Hi all, Does Newton's law of universal gravitation depend on the geometry of the manifold? For example, what happens to formulas if we take the projective plane as our universe? How can one model "the mass" on the projective plane or on torus? I am a math grad with very elementary...

Homework Statement A 450kg satellite is to be placed at an altitude of 2.45 x 10^6m above the Earth surface. Calculate the period the satellite will have when orbiting at that altitude. Homework Equations m2g = Gm1m2/R^2 = m2v^2 = m2(4pie)^2 R /T^2 = m2 2pie v/T Ac=4pie ^2 R / T^2...

Homework Statement Mars travels around the Sun in 1.88 (Earth) years, in an approximately circular orbit with a radius of 2.28 x 10^8 km Determine a) the orbital speed of Mars (relative to the Sun) b) the mass of the Sun Homework Equations acceleration centripetal = 4(pi^2)(r) /...

Homework Statement The mass of the Moon is 7.36 x 10 ^ 22 kg. At some point between Earth and the Moon, the force of Earth's gravitational attraction on an object is canceled by the Moon's force of gravitational attraction. If the distance between Earth and the Moon (center to center) is 3.84...

Homework Statement Some people say that the tides on Earth are caused by the pull of the moon. Let us investigate whether this is true. (a) Determine the forces that the moon and the sun exert on a mass, m, of water on Earth. Your answer will be in terms of m with units of N. (c)...