# What is Gravitational acceleration: Definition and 119 Discussions

In physics, gravitational acceleration is the acceleration of an object in free fall within a vacuum (and thus without experiencing drag). This is the steady gain in speed caused exclusively by the force of gravitational attraction. At given GPS coordinates on the Earth's surface and a given altitude, all bodies accelerate in vacuum at the same rate, regardless of the masses or compositions of the bodies; the measurement and analysis of these rates is known as gravimetry.
At different points on Earth's surface, the free fall acceleration ranges from 9.764 m/s2 to 9.834 m/s2 depending on altitude and latitude, with a conventional standard value of exactly 9.80665 m/s2 (approximately 32.17405 ft/s2). Locations of significant variation from this value are known as gravity anomalies. This does not take into account other effects, such as buoyancy or drag.

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1. ### Gravitational acceleration magnitude - confused

The given answer is g/4. But when I substituted R/4 into the radius, I get 16GM. Am I just using the wrong equation altogether? He also said that you also got g/4 if the distance was 2R.
2. ### I Gravity inside an exponential mass disk

I am trying to understand gravity inside an exponential axysymmetric mass disk with no thickness. I know there are exact solutions for this case, such as the Mestel disk or the Kuzmin model, but I want to work out a simpler solution. I am approaching the subject by linear superposition. For a...
3. ### B Gravitational acceleration and sub-atomic electric charge

Wak a ball with a bat and the ball accelerates. Now under gravity, hold the ball out horizontally, let go and the ball accelerates ... without a wak. Given that gravity arises from curved space-time, I suggest further that the acceleration of the ball arises when sub-atomic particles (in the...
4. ### B Gravitational acceleration in circular motion

Hi guys, I have a question that is simple but I do not know how to answer that. It is the following, where does the acceleration of 9,8 meters per second squared go when We're dealing with uniform circular motion? I know that We have the centripetal acceleration that is a vector change, but the...
5. ### Calculate gravitational acceleration without mass of both objects

I haven't gotten anywhere. I don't find it possible to calculate this since Fg varies based on the Mass of the meteroide and because of that it will change acceleration. I thought about trying to remove m1 by making F=m*a the same as 𝜸(m1*m2)/r^2 since I think they are the same force. m*a=...
6. ### B Finding Gravitational Acceleration

Hi if I understand it correctly, this is the process to find freefall acceleration of a falling body. S=ut+1/2at^2 Initial time and displacement is zero so, S=1/2at^2 find acceleration a=2(S/t^2) graph for change in displacement over time squared a= 2(yf-yi/xf-xi) (f=final i= initial) I...
7. ### I If gravity is not a force, what is holding us down?

OK. Gravity is not a force it is a contraction or curvature of space. I was free-falling and now I hit the ground. Why don't I float through the universe, or go upward instead of still trying to go downward. Because I hit the ground, and now there is no force(like gravity) and my free-falling...
8. ### Is Gravitational Acceleration Positive or Negative in Upward Motion Problems?

I attempted the question with d=vi x t + (at^2)/2 gravitation acceleration= -9.8 and I got the solution of 22.724. Should I use the value of -9.8? or should I just use 9.8? should I use the equation above? I feel like what I am calculating is not displacement but distance... thank you
9. ### I Gravitational potential gradient in accelerated reference frames?

Hi, Could you please help me to clarify the following problem? In the gravitational field of a mass, the force on a body in steady state comes from the gradient of the gravitational potential - or the gradient of speed of time. But what about accelerated reference frames? I assume that there is...
10. ### Solving Symbolically: Height of Cliff with No Air Resistance

Homework Statement You are climbing in the High Sierra when you suddenly find yourself at the edge of a fogshrouded cliff. To find the height of this cliff, you drop a rock from the top; a time T later you hear the sound of the rock hitting the ground at the foot of the cliff. a. If you ignore...
11. ### How to find the acceleration due to gravity inside a planet?

Consider a spherical planet of uniform density ρ. The distance from the planet's center to its surface (i.e., the planet's radius) is R. An object is located a distance R from the center of the planet, where R < Rp. (The object is located inside of the planet.) 1) Find an expression for the...
12. ### Gravitational acceleration based on density

Im trying to create or find some way to calculate gravitational acceleration on planet surface based solely on density and mass of planet. This should be based on average density and it can be also some approximation, without calculating minor effects like rotation, planet bulge, relativity and...
13. ### I Gravitational time dilation - acceleration vs potential

What I know gravitational time dilation (based on GRT) is dependent on gravity potential and not on gravitational acceleration. That would mean, that for example in center of Earth is the gravitational acceleration zero, but the gravitational potential is bigger than on the surface of Earth...
14. ### How do write the force diagram for the following situation?

Homework Statement We have a crate sitting on a scale that is on the surface of the Earth. We want to come up with the value of the acceleration due to gravity, ## g ##, when we take into consideration the rotation of the Earth. Homework Equations In the book, here's how they go about this...
15. ### What is the relationship between kinetic energy and gravitational acceleration?

Hello. I am in a 100 level physics college course and we are learning about conservation of energy. I am working with a program called Logger Pro. I've attached my data in the pictures. Here is a question that I am very much stuck on. Using the Law of Conservation of Energy, show that the...
16. ### I Answer: Understanding the Effect of Gravity on Falling Objects

You are launched upward inside a railway coach in a horizontal position with respect to the surface of Earth, as shown in the figure. After the launch, but while the coach is still rising, you release two ball bearings at opposite ends of the train and at rest with respect to the train. a)...
17. J

### Why is a Newton of force .225 pounds?

General physics question regarding force and gravity. Hypothetically speaking if every piece of mass weighed double. If something that weighed 1 Pound is now 2 pounds. If you weigh 100 pounds now you weigh 200 pounds . Assume gravity is still 9.8ms/sq. and you never experience gravity any...
18. C

### Projectile motion -- how long does it take the projectile to reach maximum height?

Homework Statement A projectile was launched at 70 m/s at an angle of 45 degrees above the horizontal, how long does it take the projectile to reach maximum height? Homework Equations Vyo= initial vertical velocity Vo=initial velocity The Attempt at a Solution I tried using the...
19. ### Weight measurements and gravitational acceleration

Hi all, Since the gravitational acceleration varies depending on location, then how do you know if your scale is precisely calibrated? If I use a calibration weight (e.g. 100.000000 g) that was manufactured and tested around at equator where g=9.780 m/s^2, in my lab at the north pole where...
20. ### Need help with gravitational acceleration SI units

Please ignore strikeout (not sure why post is doing that) I just watched a video from Caltech (Video link at bottom of post) It says: Displacement = Distance Fallen in first second of time in [m] * Time2 so Time2 has no si unit as it is just a ratio right? Instant or Average Velocity = 2 *...
21. ### I Fundamental laws time reversal

It is often told that fundamental laws are insensitive to +t/-t change. Let's try this one: a little mass m1 object is accelerating towards a big object M2, in -x direction in space and +t in time, due to gravity or following space-time free fall line (along a geodetic). Now, revert the video...
22. ### Confusion about gravitational acceleration

I understand that gravitational acceleration is independent of mass. However, I've seen a common mathematical description of this that I can't help but find circular. I suspect that there's an error in my thinking that I'm hoping someone can point out for me. It goes like this; ##F=mg## but we...
23. ### Height differences from relative uncertainty of gravimeters

Homework Statement The best relative gravimeters have a relative uncertainty of 10-12, that corresponds to a height difference of 3 µm. Homework Equations g∝(1/r2) The local gravitational acceleration g outside the Earth is proportional to 1/r2, which means (Δg)/g = -2 (Δr)/r. With (Δg)/g =...
24. ### Equation for plasma wave/light speed travel?

Hi guys I'm finishing up some promo art for my original comic book. You're seein it here first. But its missing something- an appropriate equation. I would like to integrate a math equation into the art. I am attempting to depict FTL travel, using qualities similar to an LWFA, the plasma being...
25. ### Change in Earth's gravity & rotational KE due to changes in Radius

Homework Statement Let g be the acceleration due to gravity at the Earth's surface and K be the rotational kinetic energy of the Earth. Suppose the Earth's radius decreases by 2%. Keeping all other quantities constant, (a) g increases by 2% and K increases by 2% (b) g increases by 4% and K...
26. ### I What would happen in following condition?

If a conduction band is placed in a current loop with gravitational waves acting upon it in parallel direction. It is also assumed that all the basic conditions relating to frequency are met for parallel propagation case as per gravitational wave damping papers below. Since nuclear precession...
27. ### How is gravitational acceleration affected with distance?

Note: I didn't really know where to put this. It isn't a specific problem, but I've been asked by my physics teacher, who decided to give me and a few others an individual physics course of sorts, to find the means of solving similar problems. It's the first problem he assigned us, since we're...
28. ### I Consequences of Rotating Objects C on Coil A Frequency

As per the above figure coil A is situated inside a magnetic field caused by small accelerating objects B which in turn are causing the larmor frequency in coil Object C or train of objects C have quadruple movement and are rotating around the coil A giving out gravitational waves. Objects C...
29. ### I Particle accleration under gravitational waves?

I have been through following papers for research: 1)http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1990ApJ...362..584M&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf 2)https://arxiv.org/pdf/gr-qc/9905054.pdf Conclusion of the second paper given above...
30. ### Finding the speed of the comet

Homework Statement Comets travel around the sun in elliptical orbits with large eccentricities. If a comet has speed 2.2×10^4 m/s when at a distance of 2.6×10^11 m from the center of the sun, what is its speed when at a distance of 4.2×10^10 m Homework Equations L = rp = r(mv) The Attempt at...
31. ### Finding the astronaut's weight on a planet's surface

Homework Statement A landing craft with mass 1.22×10^4 kg is in a circular orbit a distance 5.50×10^5 m above the surface of a planet. The period of the orbit is 5100 s . The astronauts in the lander measure the diameter of the planet to be 9.50×10^6 m . The lander sets down at the north pole...
32. M

### I Gravitational acceleration and the baryon distribution

<<Mentor note: Moved from this thread>> I read this article http://thedaily.case.edu/rotating-galaxies-distribution-normal-matter-precisely-determines-gravitational-acceleration/ It claims that the rotation of galaxies can be explained without a need for dark matter. I not an educated...
33. ### B How do I calculate electron acceleration by gravitational waves

If the amplitude of gravitational waves, frequency of gravitational waves and the vector potential of magnetic field in surrounding of such waves are known then what would be the easiest way to calculate resultant acceleration of electrons? My above question is based on the various researches...
34. C

### Calculating the Height Needed to Break the Sound Barrier When Dropped

Sooo i was wondering... Can something that has been dropped from a higj enough hight eventually break the sound barrier. Well, since we know that the gravitational acceleration is approximately 10 m/s^2 and that the speed of sound is approximately 330 m/s i pluged it into the acceleration...
35. ### Newton's first law, forces, charges

Homework Statement Two uniform masses of .260kg are fixed at points A and B. Find the magnitude and direction of the initial acceleration of a uniform sphere with mass 0.01kg released from rest at point P that is acted on the gravitational forces of attraction from spheres A and B. The diagram...
36. ### Bernoulli Equation - sign of gravitational acceleration

Homework Statement Water flows from the faucet on the first floor of the building shown in the figure with a maximum velocity of 20 ft/s. For steady inviscid flow, determine the maximum water velocity from the basement faucet and from the faucet on the second floor. Assume each floor is 12 ft...
37. ### College physics problem -- Find gravitational acceleration

Homework Statement Here's the question: As space colonization expands, it's important to build new stations from local materials instead of bringing everything from Earth. Your latest task (besides asking for a raise) is to check the long-term stability of a proposed configuration of asteroids...
38. ### Gravitational acceleration comparison

Homework Statement Suppose an object of length “l” is located a distance “r” from a gravitating object of mass “M.” From physics you will learn that the gravitational acceleration is GM/r^2. Derive the difference in gravitational acceleration between distance “r” and distance “r+l” from the...
39. ### Gravitational acceleration (g) is used as constant, but is it?

Acceleration due to gravity is used as a constant throughout the massive body,but it varies due to height and depth & also varies from equator to pole,so it affect the rotational speed of planet from equator to pole.So, why would it takes as a constant.
40. ### Deflection of gravitational acceleration vector due to Sun or Moon

On Wolfram Alpha, I get the following values for gravitational acceleration on Earth due to the sun and moon, respectively: gravitational constant * mass of sun / (distance to sun)^2 → 0.005991 m/s2 gravitational constant * mass of moon / (distance to moon)^2 → 3.68×10-5 m/s2 If the...
41. ### Calculating sand penetration of ice solid from height X

G’day physics forum This is a purely hypothetical question and my knowledge of physics is rather limited so I’ve no idea if answering it is even possible however here goes: Imagine a 30cm long timber stick approximately 3mm in diameter that has been placed vertically in an inverted pyramid or...
42. ### 1g (gravitational acceleration) Sphere of U238

How big would a sphere of U238 have to be to reach 1g at its surface?
43. ### Why is gravitational acceleration regarded as a constant?

I am hoping to recover some of the knowledge of physics I gained in high school that has vanished into the mists of time. Currently, I am being abused on Facebook by a self-proclaimed authority who ridicules my contention that gravitational acceleration is a constant. I get the idea that gravity...
44. ### A speed equivalent of gravitational acceleration?

Things space contract and time dilate in SR. And also things space contract and time dilate near heavy objects in GR, right? Particles are accelerated towards heavy objects in GR. My question is does the the acceleration due to gravity produce a frame of reference equal to some speed which...
45. ### Frequency dependence of gravitational acceleration

Imagine a massive object emitting photons of various frequencies. Because the object is massive, it will exert gravitational acceleration on those photons. Because the energy of a photon is proportional to its frequency, it seems that higher-frequency photons will experience a higher magnitude...
46. ### Separating out centripetal and gravitational acceleration

Has anyone got any experience of this using a dual axis sensor on a pendulum? I have attempting to do itt however I am not completely satisfied that my method is successful
47. ### Gravitational acceleration, cosine problem

Homework Statement The gravitational acceleration at latitude x (0<x<90) can be estimated with g(x)=a*cos(2x)+b. 1) Determine what a and b is if the gravitational acceleration is 9.780m/s^2 at x=0 and 9.832m/s^2 at x=90. Homework EquationsThe Attempt at a Solution So I begin by entering what...
48. ### Gravitational Acceleration Question

Homework Statement Calculate the maximum gravitational attraction between a man and an apple, when a) the apple was 1m from the man's center of mass, b) the apple hit his head. (man's mass 60kg, apple mass 100g) Homework Equations F=G(m_1)(m_2)/r^2 F=ma The Attempt at a Solution I set up the...
49. ### Gravitational acceleration problem

Homework Statement Alice and Bill are at the top of a building. Alice throws her ball downward. Bill simply drops his ball. Which ball has the greater acceleration just after release? Homework Equations force, F=ma and F=mg The Attempt at a Solution Alice: F=ma+mg=m(a+g) Bill: F=mg...
50. ### Gravitational acceleration towards and through an object

Take a hypothetical object with an infinite density (purely so that a particle can get incredibly close to it). Furthermore imagine that this object has no close range repulsive force, or in other words, particles can pass right through it. The only thing is does is exert a standard...