Gravity force Definition and 33 Threads

Why for gravity some things like planets, stars are heavy enough to have a gravity so they don't fall of the space? When a small object can free fall in space, why a planet has a gravity, and they are considered heavy to what formula?

I could understand the problem perfectly; however, I do not know how to construct the problem. The problem states that two forces are acting simultaneously on the object, but how could I represent that fact mathematically? I really want to solve it, but I am facing this roadblock, so please...

A relatively simple question has been bothering me for some time: Why is the weight of an object (the force the object exerts on a surface/rope) equal to the force of gravity that the body experiences in Earth’s gravitational field? Earth’s gravitational field accelerates all bodies in its...

Hello everyone, I have the problem above. I chose to put ##F_G = F_Z## to solve it and end up with a radius ##r = 1.04\cdot 10^{-7}##m. Solutions on the internet choose to put the gravitational force equal to the centrifugal force and obviously end up with a completely different solution. I...

First, if we sign the speed in the highest point of the ball's trajectory to be ##v_2##, we can write ##m\frac {{v_2}^2 }{l}=T_2+mg-\frac{1}{4\pi \epsilon}\frac{Q^2}{l^2}##. Now, depending on the ball's particular mass, the electrostatic force can be bigger of smaller than its gravity force...

This problem builds on my previous post, where we calculated that core's mass is ##M_1=\frac{{v_0}^2r_1}{G}##. So if we consider mass of dark matter dependent on distance ##r## to be ##M_2(r)##, we can calculated it from ##G\frac{(M_2(r)+M_1)m}{r^2}=m\frac{{v_0}^2}{r}.## So...

The center of gravity of a circular wire should be in its center? What would happens if we put a marble and a wire into an empty space. Would the gravity force skyrocket as the marble approach the wire center of gravity?

Im prototyping a machine to lower liquid from a height using a chains and sprockets. Essentially liquid will fill at top, be lowered over a distance of 4.8 metres then emptied at bottom. The liquid needs to be lowered at a slow pace due to resistance on the output shaft, I am considering...

Can someone help me to calculate the approximate impact on the Earth (as in a mining explosion), of 1 ton of dynamite. And also the equivalent impact of say a 1 ton rock dropped from 10 meters. Trying to estimate this for writing purposes, I very roughly got: Impact of 1 ton of dynamite, Work...

1Problem: Two equal satellite, A and B, of a planet of mass M, describe circular trajectories where the radious are 0,5r and r. We can afirm that: A- The intensity of gravitical force acting on B is half of the gravitical force acting on A; B- The value of centripetal aceleration of A is one...

Hello Please why the mass m3 does not fall?

So I understand the relationship between mass x acceleration=force but all that relationship tells me is "Whatever the force is to accelerate a given mass at a specific unit of acceleration = units of force, and we just accept whatever the unit of force is. example 1/ms² x 1 kg mass = 1 N...

Is it possible that the reason why gravity is the weakest fundamental force is because it is disappearing into the distant future? Similar to string theory's notion that gravity dissipates into other dimensions, only in this case it is time it dissipates through? Radon 220 and radium 224 nuclei...

I have this question on my practice test that I can't figure out. "Just as one jumps out of a plane what is their gravitational force given that the mass is 70kg." The thing is, for me to use the gravitational force formula I need to masses. The test only has the one. Am I missing something? Am...

Dear PF Forum, Can we avoid spaghettification for some times, once we're inside event horizon? I choose a rather massive black hole, so the tidal force won't be so big at EH. Mass: 1 trillion solar mass Schwarzschild radius: 2.950 trillion KM What is the gravitational force at EH? I calculate...

Homework Statement Hello the text is in swedish but ill try my best to translate, What it says is: Determine the resultant force on the moon with regard to thr gravitation force from the sun and the Earth when it's in this position shown in the figure [ picture http://m.imgur.com/AfJOVZo ] J...

Homework Statement A 4 kg book sinks a distance of 5m in the ocean starting from rest. The volume of the book is 0.00266666666666667 m^3. We assume the velocity of the Earth is zero during the whole process, and gravity and the bouyance force are the only interactions of the book. (Note...

Isn't the force of gravity just a result of the shape of space as it is affected by masses within it? Why is it believed that it is a force associated with theoretical force particles "gravitons"? I can understand that the electric or magnetic force is a product of particles with fundamental...

Force is naturally associated with something acting on anything. Eletromagnetic forces are bipolares, i.e., charges are of opposite signals to atract one another. Why gravity is monopolar ? The einsteins elastic rubber example imply on a kind of hyerarchy of forces, so, it would possible that...

Homework Statement In t=0 a car is free from it's chain and can fall freely through a inclined plane (10 degrees) rear wheels weight 500 lb each one and have an diameter of eight feet. Front wheel weights 800 lb and have a radius of 2 feet. The body of vehicle weights 9000 lb. Assume that...

This is not a problem statement this is not homework this is not a textbook exercise. This is my own question about a formula in a textbook. I was given an infraction because I did not post this here. Homework Statement Source: Fluid Mechanics 2nd ed. - P. Kundu, I. Cohen.pdf I am...

When we look into the molecules, there are proton neutron and electrons, as we know there is an attracted force between positive and negative charges. Does anyone have any suggestions on what generate the Gravity force from mass? Thanks in advance of any suggestions

---------------------------------------------------------------------------- I know about the shell theorem and that the force of gravity due to the mass of the spherical shell is zero inside. I have some questions that may easily be answered for other special cases using the shell theorm and...

Hi all guys, for what I have understood from general relativity theory, gravity force is "just" a space-time distortion as a result of peculiar property of matter having mass. So it is not a real force, or saying with different words, if I'm in a lab without window, in a gravitational field...

Why do specific object movement is conditioned by the gravity force? Why the moon is pulled by Earth and doesn`t move freely? Why the planets don`t move in different way but obey to the gravitacional force of Sun? Everybody knows that Earth moves around the sun for 1 year and travels for...

Homework Statement Q= 2800N G= 10m/s^2 s=35m t=10s __________ Fst=? (st-String tension) Can anyone help me with this, i have a test tomorrow And if anyone can give me the formula for the Tension force i'd be really grateful.

Homework Statement When the Earth, Moon, and Sun form a right triangle, with the Moon located at the right angle, as shown in the figure , the Moon is in its third-quarter phase. (The Earth is viewed here from above its North Pole.) Find the magnitude of the net force exerted on the Sun. Find...

The gravity force between ourselves and the objects around us is extremely small as gravity is a very weak force. The electric force is far stronger than the gravity force. Since we and the objects around us are composed of charged particles, why don’t we experience huge electrical forces...

A ball is thrown in the air at 44 m/s. How high does it go? How do you work this out?

I have this question: A 28 lb suitcase is pulled up a frictionless plane inclined at 30 degrees to the horizontal by a force P with a magnitude of 18 lb and acting parallel to the plane. If the suitcase travels 15 ft along the incline, calculate: (a) the work done on the suitcase by the...

At the surface of Jupiter's moon Io, the acceleration due to gravity is 1.81m/s^2 . A watermelon has a weight of 49.0N at the surface of the earth. In this problem, use 9.81m/s^2 for the acceleration due to gravity on earth 1.) What is its mass on the surface of Io? 2.) What is its...

Apart from C, P and T violation in weak interaction, do the same violations occur for the other three forces, in particular, the quantum gravity force?

How much will be the gravity force between two weights each of which with 1 kg at zero distance? If you ask Newton the answer will unconditionally be infinity but Archimedes would say extreme for sure but not necessary infinite. Here is why: The force in Archimedes’s physics is more like...