Gravitational potential energy Definition and 292 Threads

Homework Statement A 3.0 kg object travels vertically at a constant speed of 2.0m/s. What is the increase in gravitational potential energy after 4.0 sec? Homework Equations Ep=Mgh The Attempt at a Solution I know i need to find the height but, with constant velocity i don't know...

Homework Statement A simple pendulum is swinging. Its mass is m and its length is L. What is its gravitational potential energy if it is oriented at 30° with respect to the vertical? (Let gravitational potential energy be zero if it is in the vertical orientation). Homework Equations U =...

Homework Statement A watermelon with a mass of 2.0kg falls out of a tree house that is 5.4m above the ground. What is the speed of the watermelon just before it hits the ground? Homework Equations Δh = (vi^2 - vf^2)/2g Eg = mgΔh Ek = 1/2mv^2 The Attempt at a Solution I tried two...

Homework Statement Explain why the kinetic energy of the skier at the bottom of the hill is not equal to the gravitational potential energy of the skier at the top of the hill. Homework Equations n/a The Attempt at a Solution I think the answer is because the bottom of the hill is...

Homework Statement Four masses m are arranged at the vertices of a tetrahedron of side length a. What is the gravitational potential energy of this arrangement? (answer is -6Gmm/a) Homework Equations gravitational potential energy = -Gmm/r The Attempt at a Solution One mass is "a"...

How did scientists derive the formula -GMm/r=Ep in order to calculate the amount of work required to move an object from an infinitely large point (or an extremely large distance as my textbook says) ?

So, the gravitational potential energy of a mass "X" from the sun is, let's say, 100joules. Why is it that when we take the gravitational potential energy of the mass from the reference point of infinity that the gravitational potential energy is -100joules? I understand the negative...

Hi! So, when we're calculating the potential energy of a mass in space we make it negative because we assign infinity as the reference point. Now, to find the potential energy of something I understand that we find the work that is done to it to move it from the reference point to another...

Homework Statement a satellite having a mass of 1800 kg orbits the Earth at a distance of 6.3 x 10^5 m above the surface find the gravitational potential energy of the satellite while in orbit, the orbital speed and the binding satellite. The Attempt at a Solution gravitational potential...

Homework Statement A satellite of mass 750kg is changed from an orbital radius of 7000000m to a geostationary orbit of 4.2*10^4. Calculate the change in its gravitational potential energy Mass= 750 Earths radius= 6380000m Gravitational constant= 6.67*10^-11 Earths mass=6*10^24...

Homework Statement A satellite is in a circular orbit 655km above Earth's surface. Determine the magnitude of the gravitational acceleration at this height. Homework Equations Eg=mgh Eg=-GMm/r The Attempt at a Solution Would I just set the aforementioned eqations equal to each...

Using taylor series expansion to prove gravitational potential energy equation, GMm/r=mgh at distances close to the earth. R= radius of the Earth h= height above surface of the Earth m= mass of object M= Mass of the earth U = - GmM/(R + h) = - GmM/R(1+ h/R) = - (GmM/R)(1+ h/R)^-1 do a...

I am a bit confused about gravitational potential energy near the earth, namely the formula given by mgh. I know that potential energy is defined as U(x) = -W(x0 to x) where x0 is our chosen reference point. Let's take the Earth's surface as the zero point and let's travel upwards to a point...

I was wondering if dark energy might actually be gravitational potential energy. If one assumes that space is flat and that the Universe is approximately a sphere with mass M and the Hubble radius R then we find that we have the approximate relation: \frac{G M }{R} = c^2 A mass m...

Homework Statement The mean diameters of Mars and Earth are 6.9 10^3 km and 1.3 10^4 km, respectively.? The mass of Mars is 0.11 times Earth's mass. (a) What is the ratio of the mean density of Mars to that of Earth? (b) What is the value of the gravitational acceleration on Mars...

datum 1 --------- E1=K1+G1+S1 =0+8(9.81)(-3)(sin37)+0 =-141.69 datum 2 --------- E2=K2+G2+S2 =1/2(8)(v^2)+0+0 = 4v^2 Frictional Force: 0.15x9.81.8 = 11.772Newtons U1-2= -11.722x2 = -23.544J E1+U1-2=E2 -144.69-23.544=4v^2 -42.0585=v^2 Can't square root...

Is there Gravitational Potential Energy on a horizontal surface? Example from Position 1 - 2

Is what I am currently reading about. The book I am reading presents it by giving an example; it proposes lifting a mass without any acceleration through a height, h, with an upward force equal and opposite to its weight. Does that mean the net work done on this mass is zero? My hand still does...

I have attached a discussion by R.Feynman where he derives the formula for gravitational potential energy using pure reasoning. I don't quite follow the reasoning and I have read the discussion many times yet can't get a grasp of things he says. With the discussion I have my doubts in red...

Hey guys, I'm currently trying to get my head around the concept of gravitational potential energy; U_{r} = -\frac{Gm_{1}m_{2}}{r} My question concerns whether this relates to both bodies in the system individually, or together. That is, if I have two masses separated by a distance...

Homework Statement What is the gravitational potential energy of a car with centre of mass at a height h above the ground? On a level road the centre of mass is at a height of 0.1m above the ground. Homework Equations gravitational potential energy=mgh The Attempt at a Solution I would use...

Hello all, I'm new to the forum here and desperately need some help in some basic physics concepts that I need to have a firm grasp on for the MCAT. My question is about PE on an inclined plane. For example, there are 3 possible scenarios (the height and mass remains the same for each...

Just a little confused, when work is done on an object it's energy increases right? (i.e. Work done on object = Change P.E + Change K.E + Work done by object) So how come when gravitational force does work on an object(i.e. it falls) the potential energy decreases instead. So its like Work...

Why is gravitational potential energy relative to the height you set? When I say relative, I don't mean anything having to do with relativity. Obviously as you go further from the earth, you have more potential energy but in the equation Ug=mgh if you set the height to 0 there is no potential...

Homework Statement A piece of fruit falls straight down. As it falls, A. the gravitational force does positive work on it and the gravitational potential energy increases. B. the gravitational force does positive work on it and the gravitational potential energy decreases. C. the...

Homework Statement An archer places a 0.15kg arrow on a boasting. Then the archer exerts an average force of 100 Newtons to draw the string back 0.45 meters. Assume that friction is negligible. A) what speed does the bow give to the arrow? (5 marks) B) If the arrow is shot vertically...

Homework Statement A 4.0 kg mass is pressed down on a vertical spring of spring constant 400 N/m, compressing it to 0.250 m. After it is released, the amount of kinetic energy this mass would have when it leaves the spring is ___. Homework Equations mgy(final) + 1/2 kx^2 (final) + 1/2...

Feynman's lecture on physics: chapter 4 derives equation for gravitational potential energy by a "lifting 3 balls" example. The book notes: "But the strange thing is that, in a certain way of speaking, we have not lifted two of them at all because, after all, there were balls on shelves 2 and...

Homework Statement The gravitational self potential energy of a solid energy of a solid ball of mass density p and radius R is E. What is the gravitational self potential energy of a ball of mass density p and radius 2R? Homework Equations The Attempt at a Solution The...

Hello, I thought of asking would someone know what is the correct thinking here... A body is thrown upwards, its kinetic energy gradually transforms into gravitational potential energy until it is entirely absorbed. At this moment, where is the potential energy? According to wikipedia (N...

Homework Statement A 1000kg roller coaster, with its passengers, starts from rest at point A( h= 9.5 m) on a friction track whose profile is shown in the diagram above at right. a) what is its maximum speed? b) with what speed does the roller coaster arrive at point e? c) What constant...

Homework Statement Question: Rank the paths according to the corresponding change in the gravitational potential energy of the rocket–moon system, greatest first. A. 1 > 3 > 5 > 2 = 4 = 6 B. 2 = 4 = 6 > 5 > 3 > 1 C. 1 = 2 = 3 = 4 = 5 = 6 D. 1 > 2 = 4 = 6 > 3 > 5 The Attempt at a Solution...

Explain how a skier can have more than one value for gravitational potential energy at anyone time? My attempt at an answer. Consider the position of the skier is relative to the bottom of the hill. Therefore the skier has gravitational potential energy as he/she descends down the hill. At...

In the Proof of the Gravitational Potential Energy Law , it says : Consider two point masses , body . mass "m" and Earth mass "M" , where M remains fixed. The work done to move the mass "m" from point 1 to point 2 is given by : W(1-2) = ∫FG . dr (All in vectors) = ∫FG Cos 180° dr ( All in...

In my book it is talking about conservation forces and work energy theorem. In the book it said... "suppose gravitational potential energy alone does work (constant force) *Then Wnet = Wg ... ending statement Ef = Ei... My question... Does the work energy theorem only deal with...

Homework Statement A marble is placed at the top of an inverted hemispherical bowl of radius R = 0.30 m. It starts from rest and slides down the bowl without friction. Draw a free body diagram when the marble reaches an angular position θ = 16.6°. From your FBD, sketch the approximate...

Hey guys So if I lift a book from the ground it gains potential energy. I do work on the book and when I release it the potential energy that I gave the book pulls the book back down to Earth. However I was looking at a potential energy formula for planets which was V = -GMm/r But...

Homework Statement A 400-N child is in a swing that is attached to ropes 2.00 m long. Find the gravitational potential energy of the child–Earth system relative to the child’s lowest position when (a) the ropes are horizontal, (b) the ropes make a 30.0° angle with the vertical, and (c) the...

Homework Statement An object is moved from A to B in the gravitational field of earth. The distance between the center of Earth and B is twice that of A. If the gravitational potential energy of the object at A is -2MJ, what is the gravitational potential energy of the object at B?Homework...

I want to propose that Gravitational Potential Energy (GPE) is a renewable energy input source but I feel maybe GPE might not be accepted as part of the surroundings acting upon the energy boundary of a system. What are the rules of the energy boundary that umpire what is allowed and...

Hello, having had an interest in physics for a while I recently enrolled on an access to higher education course to study it. Unfortunately I seem to have fallen at the first hurdle. First off I'd like to apologise profoundly and profusely for the simple problem you are about to read, but I have...

This may have been answered elsewhere but I couldn’t find it. Is it the case that gravitational potential energy will add mass to an object the same way nuclear binding energy will? In other words, as I move an object away from Earth is it gaining mass in the form of the stored energy I put...

Homework Statement I have learned that gravitational potential energy's formula is: GPE = mgh But I saw other formulas relating to gravitational potential energy: \phi = -G(m/r) And then one formula like this: F = dU(x)/dx And then there's a formula relating to the CHANGE in...

In this investigation I had to calculate my maximum power as I run up a flight of stairs. These are a few questions that I have for my lab. I want to know if my calculations are right. Given: 1. mass: 70kg 2. h = 1.17m 3. d= 1.78m 4. t = 2.02s Use the information from 1 and 2 to...

Hey, I have a test tommorow and I don't really understand gravitational potential energy or kepler's laws. It's not really a theory test, it's the math aspect, but I still don't understand it. I know of the formulas such as Fg=Gm1m2/r^2, Eg=Gm1m2/r, Ek=1/2 mv^2, and I think that's all. But...

Homework Statement Deep in space, two neutron stars are separated (center-to-center) by a distance of 18 X 106 km apart. Neutron star A has a mass of 153 X 1028 kg and radius 52000 m while the neutron star B has a mass of 159 X 1028 kg and radius 72000 m. They are initially at rest with...

Does the r in GPE=-GM/r refer to the distance an object is from the centre or surface of the object of big mass M?

Homework Statement if the angle of the slope is increased, the change of gravitational potential energy between the two heights: (Select all that apply) (It may be more that one option) increases depends on the path followed. decreases. depends only on the difference between the two...

Homework Statement [PLAIN]http://img818.imageshack.us/img818/817/potentialenergy.jpg Homework Equations Given above. The Attempt at a Solution I've never had physics in my life and am completely baffled by this problem. I'm only in calculus 3 and am just learning infinite...

Setting gravitational potential energy's zero at infinity distance, is it safe to say that the limit as r approaches zero of gravitational potential energy is negative infinity? Thus is it safe to say any object at r=0 is necessarily bound to the system, no matter what kinetic energy it has...