Gravitation Definition and 915 Threads

"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...

Hi I like to know, Why there are gravitation at all which make every matter in our daily life can attract each other? such as Earth with moon, sun with earth, Earth with human, and so on. I've searched in many source even e-source(internet source), many physics books, professor in...

Homework Statement Derive Newton's Law of gravitation using kepler's laws. Homework Equations Kepler's law equations. etc. The Attempt at a Solution l= r(1- e*cos(theta)) l- const. e- eccentricity Solving these equations using kepler's laws (r^2(d(theta)/dt), etc.)...

Consider two iron spheres, each of diameter 100mm, which are just touching. At what distance r from the center of the Earth will the force of mutual attraction between the contacting spheres be equal to the force exerted by the Earth on one of the spheres? Here's my work... d = distance...

There will be an inaugural conference to celebrate the opening of the new Institute for Gravitation and the Cosmos, on 9 - 11 August at Penn State http://www.gravity.psu.edu/igc/ http://www.gravity.psu.edu/igc/conf_files/prelim_agenda.html Here's a sample from the program. I'll skip most of...

my physics teacher told me that: 'for an object placed at the surface of the earth, the gravtitional force must be greater than the normal contact force due to the required centripetal force' it's alil bit difficult for me to understand this... and if smeone could explain to me what is the...

Announcement of the inaugeral conference of the IGC in August. http://www.gravity.psu.edu/igc/ description of what the new institute is to be like and what the purpose is http://www.gravity.psu.edu/igc/igc-web.pdf ==quote== Abhay Ashtekar, holder of the Eberly Chair in Physics and the...

hi i have some questions about Newtons law of gravitation and i need complete answers coz these qwestion will be my second exam: 1.the gravitational force between a ring of raduis a and mass m and a rod of mass m and length l lies on the central axis of the ring and the distance is x between...

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...

The Claim: "Gravitation is acceleration." Please help me understand. I'm struggling with this claim. I have a BA with a physics major (though 26 years ago), but I don't seem to be able win an argument about this claim. It's important to advancing our understanding, and I politely request your...

I was just reading through stuff about Newtonian gravitation and this question popped up in my head and I can't answer myself. Consider two uncharged point masses with mass M and m respectively, independently suspended far away from each other in a space that would otherwise consist of...

Hi, I'm trying to get the rig for my physics project set up which requires some constant water flow through the system. Unfortunately it's requiring a bit more water inflow than the tap can provide. I measured the tap's flow rate to be somewhere around 0.1L/sec to 0.3L/sec Now because I...

Homework Statement What is the gravitational force caused by a thin uniform rod of length L on a point mass located perpendicular to the rod at it's center? Assume the point mass is a distance R perpendicular to the rod. Homework Equations g = - \frac{GM}{r^2}\hat{r} = - G\rho \int...

Homework Statement Given a point P in space and a given a piece of malleable material of constant density, how should you shape and place the material in order to create maximum gravitational field at P?? Homework Equations The Attempt at a Solution Possibly I can see that the...

Does gravitational waves participate in gravitation interaction?? Does gravitational waves participate in gravitation interaction?? When gravitational waves pass through the sun ,it will deflect?? Thank you in advance!

There is a set of two problems, I can solve problem 1, can't solve problem 2. But in order for you to help me solving problem 2, I think you need to use the answer for problem 1. Homework Statement P1. A satellite hovers over a certain spot on the equator of (rotating) Earth. What is the...

Simple Gravitation - With Answer - Help me work the middle steps Homework Statement Three objects -- two of mass m and one of mass M -- are located at three corners of a square of edge length l as in Figure P13.23. Find the gravitational field g at the fourth corner due to these objects...

I'm confused about the two equations: PE_{G}=G\frac{m1*m2}{r} PE_{G}=mgh When do you use either of these equations? Can these two equations be used interchangeably or not? Also, I think I remember reading somewhere that you need to use the 1st equation when the problem involves large...

Homework Statement A gaseous planet, with radius R, has a radially dependent density function \rho (r') = \rho_0 [\frac{r'}{R}]^2 where r' is the distance from the center planet. Find the magnitude of force for a mass m inside and outside of the planet. Homework Equations F =...

Hi, I am taking Physics Grade 12 at home, so I get teacher's help for 2 hours once a week. They basically give me booklets to do at home and just simply hand it in. But the negative side to this that it's only 2 hours of help and teachers don't know most of the questions (they're new). And also...

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...

it's on centripetal force and gravitation problems.. wonderin if anyone can provide me answers such that i can compare mine here's the assignment http://www.geocities.com/cheemaharmeet/assignment.jpg mine are { 1. 8N; 2. 1.97 hr; 3. 7.9E3 m/s 4. 382.26 m, 5.49E3 N 5. 8E-10 N 6...

Hello everybody, Let’s say a rocket which is at rest relatively to an asteroid. The rocket engine start and the rocket is launched toward the asteroid’s neighborhood. When the rocket engine is working, the rocket accelerates. Few minutes later, the rocket engine turns off and the rocket is now...

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...

Hello all, I have a simple question, that has challenged my mind for quite a while now. The question is: since the moon is in orbit due to the Earth's gravitational force, why doesn't the moon crash into the Earth(and the Earth crash into the sun for that matter)? I have the assumption that...

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...

Homework Statement A sensitive gravimeter at a mountain observatory finds that the acceleration due to gravity is 5.00×10−3 {\rm m/s^2} less than that at sea level. What is the observatory's altitude?Homework Equations a=(GM/r^2)The Attempt at a Solution Gravity should be 9.8-.005=9.795 and...

Homework Statement A space shuttle of 68000 kg is placed in orbit at an altitude of 1000 km from the surface of the Earth. What energy must we provide? The Attempt at a Solution I will need to provide energy in order to decrease the potential energy and an additional energy for the kinetic...

OK...this must b simple...but I don't know how to go 'bout...it needs some integration for sure...I have also attached the diagram with it. Find the gravitation force of attraction between a particle of mass m and a uniform slender rod of mass M and length L for the orientation given in the...

Homework Statement Four 8.0-kg spheres are located at the corners of a square of side 0.50 m. Calculate the magnitude and direction of the gravitational force on one sphere due to the other three. Homework Equations F = (G*m1*m2)/r^2 The Attempt at a Solution I labeled each sphere as A, B, C...

What do you think about this book? What level of mathematics and physics knowledge is needed to understand the material?

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...

I just want to know if there is enough information for me to answer this question.. to me it just seems like i should be given some more information A satellite is designed to orbit Earth at an altitude above its surface that will place it in a gravitational field with a strength 4.5 N/kg...

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...

Consider a two body gravitating system: The gravitational potential energy for m_1 is: Gm_1 m_2/r The gravitational potential energy for m_2 is: Gm_2 m_1/r So each of their gravitational potential energies are the same. Therefore, wouldn't the total energy of gravitational waves emitted be...

A triple star system consists of two stars each of mass m revoling in the same circular orbit of radius r around a central star of mass M. The two orbiting stars are always at opposite ends of a diameter of the orbit. Derive an expression for the period of the revolution of the stars. I don't...

law of gravitation- is this better? Could someone check this please? Four identical masses of mass 600 kg each are placed at the corners of a square whose side lengths are 14.0cm (.14m). What is the magnitude of the net gravitational force on one of the masses, due to the other three...

A satellite has a orbital period of 5760s around earth. What is the orbital radius? I'm not sure how I can do this without the velocity or acceleration. Thanks,

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.

GRG 18---the 18th int. conf. on General Relativity and Gravitation (Sydney 2007) http://www.grg18.com/ I have very little information. If someone has some QG paper they might think about presenting it at GRG, Sydney Australia. the dates are 8-14 July 2007 maybe Kea knows something...

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...

Let's say, in an hypothetic situation, that the moon would explode to tiny bits. What would happen to the earth? I was said it would actually change: The orbit of the Earth *duh!* Water levels all around the world *duh!* And the point I have a problem with is this last one... It...

A couple of questions that I am struggling with again...that I really need to figure out ASAP On the way to the Moon the Apollo astronauts reached a point where the Moon's gravitational pull became stronger than the Earth's. (a) Determine the distance of this point from the center of the...

At the Earth's surface a projectile is launched straight up at a speed of 10.1 km/s. To what height will it rise? Universal gravitational constant = 6.673e-11 N m^2/kg^2 Radius of the Earth = 6.370e+6 m Mass of the Earth = 5.980e+24 kg I know to use the equation U= - (Gm1m2)/ r I also...

I'm having trouble distinguishing the values of the components in the gravitation equation for the following problem: Here is how I approached it - The equations I will be using are: F = G*M*m/r^2 W=KE KE=\frac{1}{2}m v^2 So first off, I solved for the force using the gravitation equation -...

I know it is 9.8 m/s^2. However, we're covering Kinematics, and I'm just wondering how you know whether you use -9.8 or +9.8. At first, I thought that if the object was traveling up, you would use +9.8 and if it was going down, you would use -9.8. But I just went over a problem that used +9.8...

hello all i was wondering if we could use Newton's F=GMn/r^2 to apply it to non-point masses, and specifically, if they two masses come completely within each other, would it still hold?

guys i need help with these problems.I have been trying to solve then for a long time and still cannot as i am very confused and have no where to go for help 1) On the way to the Moon , Apollo astronauts passed a point after which the moon's gravitational pull became stronger than the...