Potential energy Definition and 1000 Threads

I am wondering how this all works and am hoping to get some guidance. If a 1000 lb weight freefalls vertically from 660 ft the energy is 894,289 joules. If the fall is down a 30 degree slope that is 1300 ft long, then it takes 17 seconds and the potential energy can be said to be 53 KW. If...

Hi, I'm not sure if this is the correct section to post this. As far as I know, it is widely accepted that antimatter has "normal" gravity, and that for creating a matter-antimatter pair, you need to input the rest mass of the particle in energy (Einstein's equation). But as potential...

Homework Statement Three equal point charges, each with charge 1.60μC , are placed at the vertices of an equilateral triangle whose sides are of length 0.600m . What is the electric potential energy U of the system? (Take as zero the potential energy of the three charges when they are...

Homework Statement Given that the stretched length of a string is Δx(1+1/2(dy/dx)^2) show that the potential energy per unit length is equal to 1/2F(dy(x,t)/dx)^2 Homework Equations potential energy = kx^2 cos(kx-wt) idk really... The Attempt at a Solution The fact that the...

I am watching Susskind's derivation of Newton's F=ma from the Euler-Lagrange equations (53 minutes in) here for which he uses the Lagrangian of kinetic energy minus potential energy. I have seen this done elsewhere as well. As far as I can tell, and please correct me if I'm wrong, the only...

Why does the Dirac equation not have a potential energy term? The Schrödinger equation does, and the Dirac equation is supposed to be the special relativity version of the Schrödinger equation, no?

Is there no answer given by QM till now?... Also, on a related note, when objects move through space we consider it as a point mass for the purpose of interactions. Why this simplification? Is it due to the distribution of potential energy throughout the object when a force(contact/non-contact)...

Hello, I am self studying physics and am a bit confused with Hooke's law. Using the conservation of energy equation: (PE+KE)_i = (PE+KE)_f I don't see why the springs potential energy (½ kx^2) goes in the final part. Could someone please explain? EDIT: Also, (I'm a new user) can you...

Homework Statement Hello. Imagine a particle bound in a square well potential of potential energy V0 if |x| > a 0 if |x| < a The wave function of the particle is: (ignoring the time dependency) -A*exp(kx) if x<-a B*sin(3*pi*x/4a) if |x|<a A*exp(-kx) if x>a where k =...

I am reading 'Classical Dynamics: A Contemporary Approach' by J. Jose, and I am confused about a step in the author's development of potential energy for a system of many particles. He begins by writing down a term equivalent to the total change in kinetic energy of the system: \sum_i...

Hello! I'm having some problems with a question that my professor has given me. Below is the question. I have already figured out the planet's orbital and angular-orbital velocities, but included that part due to the fact that some information was included. PICA-9 and PIC-10 are planets...

Why is dU=-\vec{F}.d\vec{r} Integrating with putting the limits on we get: ΔU=-W Why is this? Here \vec{F} is a conservative force/Force field.

This isn't a homework problem, but something that has being buzzing in my head. I've been thinking about it cause at huge distances from Earth g changes and also in what happens for really dense objected and small things could change too. The real equation for gravity no matter which body...

Explain which has more potential energy in each pair: water/glucose I think the answer is glucose since it's a bigger molecule and thus can store more energy than water. Am I right in thinking this?

Could I please have help with something: If I generated hydrogen via electrolysis from water, sent it high up a long tube then converted it back to water (via a cell or motor to reclaim energy) then, taking into account inefficiencies (or assume no energy loss), where does the energy come from...

Please explain the relation between electric potential energy and electric field in detail.

Homework Statement A conducting sphere of radius ##a## carries an initial charge ##q_o##. It is surrounded by another concentric sphere of radius ##b##. The space between the two spheres is filled with a dielectric of permittivity ##\epsilon## and conductivity ##\sigma##. Find the electrostatic...

Homework Statement Consider a circle with radius r diagrammed as the unit circle, but take only the second quadrant. On this quarter of the circle lies a chain with mass per unit length \rho (the length of the chain is \pi r/2). If \theta is the angle made with the vertical axis at any point on...

Potential Energy and Work done to lift object distance "h" The amount of energy needed to power a 0.10 kW bulb for 12 minutes would be sufficient to lift a 1 kg object how high? Power = work/time PE = mgh First I converted kw to watts which is 100 watts. Then converted minutes to seconds...

1. When taking an object and the Earth as a system, its change in potential energy is given by a. m*g*change in height b. (-m)g*change in height c. either a or b d. there is not potential energy due to gravity 3. I think it is c because the sign of energy does not matter?

U = -m x B Is B the total magnetic field of the whole system? If there is two objects X,Z and they all have a magnetic field. But different strengths, I want to calculate the U for Z, B should be the total magnetic field of BOTH fields or only X's field strength? Since X is the...

A spring with k= 53 N/m hangs vertically next to a ruler. The end of the spring is next to the 15-cm mark on the ruler. If a 2.5-kg mass is now attached to the end of the spring, where will the end of the spring line up with ruler marks? According to the book, the final reading will be 61 cm...

Hello, I'm a high school student studying for the AP Physics test tomorrow. I've been having trouble proving the negative value of gravitational potential energy through working out the work integral. I will greatly appreciate any help and clarification. Homework Statement Find the change...

Homework Statement A sphere of mass 0.1 kg is pushed against a rubber band catapult with a force of 80N, and released upwards. Calculate: A) The strain potential energy when stretched by 0.3m B) The work done by the applied force C) The speed of the sphere when released D) The...

My textbook says that the forces of intermolecular attraction between gas molecules are very weak due to large intermolecular spaces between them , that's why they're negligible , Does this have a relation with "force is inversely proportional to the square of distance " (again , I don't know...

Homework Statement A rocket is launched straight up from the Earth's surface at a speed of 1.80×104m/s . What is its speed when it is very far away from the earth? Answer in m/s Homework Equations K1+U1=K2+U2 The Attempt at a Solution .5mV1^2-(G*m*Me)/r= .5mV2^2-(G*m*Me)/r *** THe mass of...

Homework Statement Problem - Find the following: a. Potential energy in a fully compressed plastic spring. b. Spring constant This was a lab and we're supposed to do it at home, here are the variables I have measured: spring height when not compressed: 0.115 metres. spring height when...

Hello Everyone, I am having a very difficult time intuitively understanding the formula -dU/dx = Force(x). I don't want help deriving it, I'm simply looking for an intuitive understanding about why this might be true. An example with gravity would really help. My thoughts so far: I find...

I was looking at this page and it explains the heat capacity difference between copper and water in terms of a difference in potential energy change as the molecules are heated. What does that mean? I know water has polar bonding so is it due to the water molecules having much stronger...

Hi everybody, I'm reviewing for the MCAT (it's been a while), and I'm having a lot of trouble understanding potential energy. In my review book (and a whole bunch of other googled sources), it defines energy as the capability to do work. It also says work is something along the lines of, the...

and positive when they repel? It doesn't make any sense to me at all. To what are they referring to? The way I see it, if you're got... +...- The closer they are, the less electrical potential energy they have. So it should still be positive. And if you've got two like charges C...C The...

NOTE: I know this seems like quite a bit, but it's really not! Most of the questions involve simple 1-line equations, so please don't be discouraged by the amount of text - any assistance is greatly appreciated :) Homework Statement A 6kg steel ball moving at 4m/s hits a 6kg putty ball...

Homework Statement Say you have a large column of gas with insulating walls standing on the Earth's surface, which is L high and at room temperature (25degC) at the interface of the surface and column. Assuming the potential energy on the gas is only duel to gravity, U = mgx where x is the...

Homework Statement The IPA potential-energy function ##U(r)## is the potential energy "felt" by an atomic electron in the average field of the other ##Z-1## electrons plus the nucleus. If one knew the average charge distribution ##p(r)## of the ##Z-1## electrons, it would be a fairly simple...

Homework Statement Given a uniform sphere of mass M and radius R. Use integral calculus and start with a mass dm in the sphere. Calculate the work done to bring in the remainder of the mass from infinity. By this technique show that the self-potential energy of the mass is: P =...

Hello, I don't understand the second question, i don't know what I have to do: Homework Statement A string of length L, which is clamped at both ends and has a tension T, is pulled aside a distance h at its center and released. (a) What is the energy of the subsequent oscillations? (b)...

Homework Statement The figure below shows the force exerted on a particle that moves along the x-axis. Draw a graph of the particle's potential energy as a function of position from x=0 to x=1.1 . Let U be zero at x=0.Homework Equations F=-dU/dxThe Attempt at a Solution I decided to divide the...

Homework Statement A proton moves in a constant electric field E from point A to point B. the magnitude of the electric field is 6.4x10^4 N/C. The direction of electric field is opposite to the motion of the proton. If the distance from point A to point B is 0.50m, what is the change in the...

Homework Statement Suppose that a metal plate is held at an electric potential of 1.8 Volts. A proton is placed on the plate where it is repelled by the plate. What is the electric potential energy of the proton measured in Joules? __ x 10-19 Joules After the proton has moved away from the...

Homework Statement A roller coaster starts at the top of hill that is 10 m high. If it is to barely make it to the top of a second hill that is 20 m high, how fast must the initial speed of the roller coaster be? Assume that the roller coaster is frictionless. Homework Equations KE =...

A particle of mass m is in the state \Psi (x,t) = A e^{-a[(mx^2 / \hbar ) + it]}Find A For what potential energy function V(x) does \Psi satisfy the Schrodinger equation? Do I just re-arrange for A? (Sorry if I seem really dumb). I'm not really getting this.

Homework Statement A symmetric wedge of depth h and width A is filled to the brim with water of mass m, where acceleraton due to gravity is g. What is the potential energy of the water with respect to the base of the wedge? Homework Equations E = mgh The Attempt at a Solution E =...

Hi, i regard a single harmonic oszillator: $$H_{1}=\frac{p^{2}}{2m} + \frac{m \omega^{2}}{2} x^{2}$$ I know the partition function of the oszillator is: $$Z=\frac{kT}{\hbar \omega}$$ so the probability function is: $$F_{1}(x,p)=\frac{1}{Z}\exp{\frac{-H_{1}(x,p)}{kT}}$$ Now I want to...

In classical mechanics is defined potential and kinetical energy for particular particle. For example, in case of free fall potential energy of the particle is ##mgh## and kinetic energy is ##\frac{m\upsilon^2}{2}##. In QM there isn't potential of the particle, but potential of part of the...

Two charged particles of equal magnitude are located along the y-axis equal distances above and below the x-axis. Plot a graph of the electric potential at points along the x-axis over the interval -3a<x<3a. You should plot the potential in units of (KeQ)/a Let the charge of the particle...

i'm having a hard time understanding why potential energy is 0 when u(mu) is perpendicular to B(mag field). Isn't the torque at max when the angle between u and B is 90? and there for has potential to do work all the way until the angle is 0. The way my mind sees it is, since there is a torque...

This is an extract from my book ... " We define the potential V at any point in an electric field as the potential energy per unit charge associate with a test charge q0 at that point: V=U/q0." I don't know why did the book bring the test charge q0 now in the frame. Shouldn't the potential be...

Hi guys, I'm having troubles finding how to write the potential energy of a 1D pendulum down. In terms of displacement however. This should be easy and it is, but my professor had this nice "clean" solution whereas mine is really dreadfull, any help? :) edit: Ok nvm guys. I was thinking I went...

I have a general question. Is an increase in potential energy always associated with the decrease of the speed whatever the situation is. Vice verca, is a decrease in potential energy associated with the increase in the speed of the object assuming that only conservative forces are present...

Homework Statement What is the electric potential energy of a proton located 20.0 A (one angstrom or 1A is equal to 10^-10m) from another proton? Homework Equations Ep= F x d F= kq1q2/r^2 The Attempt at a Solution Ep= Fxd F=kq1q2/r^2 therefore Ep = (Kq1q2)(d)/r^2 d=r so...