Gravitational potential Definition and 389 Threads

Homework Statement The magnitude of the attractive force of gravity between two massive bodies is F=GMm/r^2, where G is a constant, M and m are the masses, and r is the distance between the centers of the two bodies. The radius of the Earth is 6.38×10^6 m and its mass is 5.97×10^24 kg. A...

Homework Statement a 18.5 kg box is slid up a 5.6 m long ramp that makes an angle of 33 degrees with the floor. What is the gravitational potential energy of the box relative to the floor? m = 18.5 kg d = 5.6 m http://musr.physics.ubc.ca/~jess/symbols/Theta.gif = 33° PEg = ?Homework Equations...

Homework Statement A person weighing 6.0 × 102 Newtons rides an elevator upward at an average speed of 3.0 meters per second for 5.0 seconds. How much does this person’s gravitational potential energy increase as a result of this ride? (1) 3.6 × 102 J (3) 3.0 × 103 J (2) 1.8 × 103 J...

Hi there, As we know gravitational potential energy is U = -GMm/R right? Here is what i obsessed, in case for the each particle can we say half of this energy belongs to one particle? I hope my question is clear enough:) Thanks in advance.

Hey guys, Do any of you happen to know how to derive the formula for General gravitational potential energy (not the mgh one) without using calculus? Thanks. Just in case you guys want to know, I'm trying to derive the equation for this: http://xkcd.com/681_large/. I've got most of it, but I...

hi, i don't really understand the meaning to GPE. if we define a point at infinity to have 0 GPE, then any point before infinity would have -ve GPE. so let's say an asteroid crashing to Earth at the surface of the Earth has initial kinetic energy of 1/2mv^2 and GPE of -GMM/r so E(total)...

1. An acrobat on skis starts from rest 50.0 m above the ground on a frictionless track and flies off the track at a 45.0 degree angle above the horizontal and at a height of 10.0m. disregard air resistance. what is the skier's speed when leaving the track? 2. K=.5M*V^2 and U=M*g*h...

Homework Statement Values for the grav potential due to the Earth are given below: dist from Earth's surface/m : grav potential/MJ kg-1 0 : -62.72 390 ...

Homework Statement (a) Determine the energy, in kW·h, necessary to place a 1.0-kg object in low-Earth orbit. In low-Earth orbit, the height of the object above the surface of Earth is much smaller than Earth's radius. Take the orbital height to be 300 km. G = 6.67*10^-11 Me = 5.97*10^24 Re =...

Is there a potential quantity in general relativity, analogous to Newton's theory of gravitation? I am not too familiar with GR, so I thought I'd ask.

Hi, I did a quick search but didnt find anything relevant so I apologise if this has been covered. My A2 Physics book says the following: My question is, the book does not go into any more detail and i am unsure what this equation is ment to actually be. I think it means G but i am...

[SOLVED] Elastic and gravitational potential energy First off, long time lurker here on his first post. Your forum seems absolutely brilliant, so I hope you can help me :) Homework Statement A box on an elastic string is dropped down an incline and proceeds to slide the distance L before...

Hello, I'm a student of applied mathematics to economics. Basic course consists of all pure math subjects. We were talking about app's of differentiating the functions u:\mathbb{R}^{n}\to\mathbb{R}^m. We defined a gradient too. In my notes is written: Gravitational potential is a function...

Are potential energy and gravitational potential energy same..?? Are potential energy and gravitational potential energy same..??:confused: Please help me...!

Homework Statement A bead of mass m slides without friction on a smooth rod along the x-axis. The rod is equidistant between two spheres of mass M. The spheres are located at x=0 , y= \pm a. a. Find the potential energy of the bead. b. The bead is released at x = 3a with an initial...

Homework Statement When finding the gravitational potential of a thick walled hollow cylinder from the point P, located along the X-axis, can I find the Gravitational potential of a solid cylinder and then subtract the gravitational potential of a smaller (inner empty) cylinder...

Homework Statement A rocket is fired straight up from the surface of the Earth at half the escape velocity. How high will it go relative to the surface of the earth? Neglect dissipative forces. Homework Equations Uinitial + Kinitial = Uf Kf is zero G*m*M/radius^2 + 1/2mv^2 =...

Homework Statement A 32.2 N child is in a swing that is attached to ropes 1.65 m long. Calculate the gravitational potential energy of the child-Earth system relative to the child's lowest position when the ropes are horizontal Homework Equations GPI=mgy Ke= 1/2 m v^2 The Attempt at a...

I read that General Relativity reduces to Newtonian when v<<c as well as when Newtonian gravitational potential energies are small compared to mc^2. What is the GR version of gravitational potential energy?

I am confused about this question: A giant star has a radius of 200 Rsun, with core of mass 0.6 Msun surrounded by an extended envelope of mass 0.2 Msun. (a) Estimate the gravitational potential energy of the envelope. When it says the envelope, does this mean the 'shell' surrounding...

Moderation Note: Split from the original thread, which can be found https://www.physicsforums.com/showthread.php?p=680746#post680746" A uniform field does not have potential difference:smile:

Homework Statement A 50.0 kg carton is dragged up a low-friction plank onto the back of the truck. The length of the plank is 3.00 m and it makes an angle of 15.0º with the ground. With respect to the bottom of the plank, the gravitational potential energy of the carton on the truck is...

Hello, I haven't learned a lot of physics and math, but I don't know how I misunderstand the following concepts: Why is the gravitational potential energy of a system of two bodies described in one term instead of two? If each body in a two-body system effects a gravitational force on the...

http://hyperphysics.phy-astr.gsu.edu/hbase/flobi.html" Since the gravitational potential energy of the falling object at the point of impact is higher than the gravitational potential energy at the distance traveled after impact, where does the energy go? It is shown that the KE is removed...

Homework Statement The distance between the sixth and the eleventh floors of a building is 30.0m. The combined mass of the elevator and its contents is 1350 kg. a) find the gravitational potential energy of the elevator when it stops at the eighth floor, relative to the sixth floor...

I recently looked at wikipedia for gravitational potential energy For two masses; M and m, and distance; r between their centres, gravitational energy; Ep is: Ep=GMMr-1 With this, the further away the masses, the smaller the potential energy the system has But this does not make...

Homework Statement A fully loaded Cessna-182 airplane of mass 1250 kg has an engine failure when flying with an airspeed of 126 km/h at an altitude of 2540 m on a calm day. It then glides at a constant glide angle (which is the direction of flight below the horizontal) towards a safe landing...

Homework Statement Find the potential at off-axis points due to a thin circular ring of radius a and mass M. Let R be the distance from the center of the ring to the field point and \theta be the angle between the line connection the center of the ring with the field point and the axis of...

A projectile is shot directly away from Earth's surface. Neglect the rotation of Earth. (a) As a multiple of Earth's radius RE, what is the radial distance a projectile reaches if its initial speed is one-third of the escape speed from Earth? (b) As a multiple of Earth's radius RE, what is...

Homework Statement a 46.0kg child cycles up a large hill to a point that is vertical distance of 5.25m above the starting position find: a.) The change in the childs gravitational potential energy b.) The amount of work done by the child against gravity Homework Equations delta Eg=mg...

After walking along the Thames every day on the way to work, I noticed that the water lever difference is between low and high tide is about 7-8m. Thoughts soon turned to how to harness this for power generation. The idea I had is to have a large weight buoyed so that it would rise with the...

Homework Statement Four particles, each of mass 60.0 g, form a square with an edge length of d = 0.700 m. If d is reduced to 0.100 m, what is the change in the gravitational potential energy of the four-particle system?Homework Equations U = -GMm/rThe Attempt at a Solution I found the U of the...

Hi there. I have a bead of mass m, which slides down a frictionless parabolic wire in the form y=x^2, and is attached by elastic to the point (0,h), and I want to write down total energy f(x) (= elastic energy + gravitational potential energy) (no mention of kinetic energy...) of the bead at...

Homework Statement A 2.40 kg snowball is fired from a cliff 10.4 m high. The snowball's initial velocity is 19.3 m/s, directed 42.0° above the horizontal. (a) How much work is done on the snowball by the gravitational force during its flight to the flat ground below the cliff? (b) What is the...

I have a technical question regarding the definition of gravitational potential energy: How correct is it to discuss/define the gravitational potential energy of object A without regard for the other bodies that are exerting a gravitational force on object A? I find this kind of thing in...

Homework Statement In a system where other gravitational influences can be discounted, two particles of equall mass m, are fixed at positions x= 0 and x= x0 on the x-axis. 1) derive an expression for the gravitational potential Vgrav at a general position x on the x-axis.? Homework...

Homework Statement A 140-N child is in a swing that is attached to ropes 2.00 m long. Find the gravitational potential energy associated with the child relative to her lowest position at the following times. (a) when the ropes are horizontal I get this one. I used PE=mgy...

Homework Statement A car in an amusement park ride rolls without friction around the track shown in the figure http://session.masteringphysics.com/problemAsset/1041727/8/YF-07-32.jpg It starts from rest at point A at a height h above the bottom of the loop. Treat the car as a particle...

Can someone help me.. A satellite of mass 100kg revolves round the Earth in a circular orbit of radius 2R where R is the radius of the Earth. Determine the energy needed to move the satellite to a new orbit of radius 3R. Thanks alot.

Hello, I am not sure how to set up this integral. Its a little more advanced than I am used too. Any ideas? Consider a thin ring of radius a and mass M. A mass m is placed in the plane of the ring (not in the center!). Determine the gravitational potential for r < a. Find a position of...

This has troubled me ever since we went over gravity in science. I didnt ask the teacher becuase i thought the answer might be obvious and I might look like an idiot in front of the class lol. But anyway, I was wondering where the energy comes from that an object has when it is in a...

Can someone please explain the answer to the question shown below: http://img152.imageshack.us/img152/1743/21985820pa0.jpg http://img61.imageshack.us/img61/2455/41357835ph4.th.jpg I know that V= - GM/r , and that allows me to sketh the answer for figure 1. Why, however, is it a...

The image below shows a sketh of gravitation potential (y axis) vs. position: http://img175.imageshack.us/img175/5717/60413547vb3.th.jpg Can someone please explain why the potential does not equal zero at the neutral point - wouldn't the two potentials cancel each other out? Thanks

Homework Statement An asteriod hits the Moon and ejects a large rock from its surface. The rock has enough speed to travel to a point between the Earth and the moon where the gravitational forces on it from the Earth and the moon are equal and opposite in direction. At that point the rock...

Homework Statement I read this statement: "The gravitational potential energy of a particle at a point with respect to another particle (kept at rest) is equal to the work done by the force which brings them from infinite separation at that point, without gain in kinetic energy." Then I tried...

Homework Statement Hey guys, just wondering if you guys could help me out a bit. A boy on a sled with a total mass of 72kg slides from rest down a hill, which is 35m high. The friction force between sled and snow has a magnitude of 250N. If the slope of the hill makes an angle of 37 degrees...

hey friends why is gravitational potential negative?

Homework Statement Two Earth satellites, A and B, each of mass each of 980kg, are launched into circular orbits around the Earth's center. Satellite A orbits at an altitude of 4500kg, and satellite B orbits at an altitude of 13600km. What are the potential energies of the two satellites...

The classical paradigm of how an object acquires gravitational potential energy goes like this: First, we take the case where the object is near the surface of the Earth which we define as the zero reference point. The object has a mass of 1 kg. We lift the object by an agent, such as a hand...

I used to wonder whether one could find a simple physical or geometric model to illustrate how the energy distribution within the universe could give rise to a local gravitational potential of the form sum(m/r), or more generally to a metric whose terms are functions of a similar sum. It...