Total energy Definition and 221 Threads

Homework Statement this is the scenario A horizontal force of 80N acts on a mass of 6 Kg resting on a horizontal surface. The mass is initially at rest and covers a distance of 5m in 0.92s under the action of the force. Assuming there are no energy losses due to air resistance and...

My group was assigned to make a lab about potential/kinetic energy and present the lab to the class. The lab we designed was to roll a ball down an incline, which then made a loop upwards like a rollercoaster, and calculate how high we need to set the ball on the incline in order that the ball...

Homework Statement Find the total energy of the following (mass m= 2 kg) oscillator. Homework Equations x=2cos(6∏t) The Attempt at a Solution Wouldn't I take my Amplitude of 2 and my period of 6 mulitply them together to get my max velocity of 12 then using KE = 1/2msquared I...

[FONT="Times New Roman"]I read from a book that the "total energy is not preserved when the potential depends explicitly on time", i.e. U(x,t). Can anyone show or prove it? Many thanks.

Homework Statement In a particle accelerator a proton and an antiproton, traveling at the same speed, undergo a head on collision and produce subatomic particles. The total kinetic energy of the two particles just before the collision is 3.2 x 10^{}-10 J. State why the total energy after...

Homework Statement Since the total energy in a spring is (1/2)kA^2 Can we rearrange this... given k=F/x (1/2)(FA^2/x) Since x is also the amplitude, we have: (1/2)(FA) (1/2)(mgA) I am pretty sure this is wrong, but why? Thanks

Homework Statement A tube is bent into the form of a semicircle with centre O and radius r. It is fixed in a vertical plane with its diameter horizontal, as shown in the diagram. A steel ball is held at one end A, and released into the tube. Throughout its motion the ball experiences a...

what is the total amount of energy radiated per second by our milky way

Homework Statement A skier of mass 70 kg sets off, with initial speed of 5 m(s^-1), down the line of greatest slope of an artificial ski-slope. The ski-slope is 80 metres long and is inclined at a constant angle of 20° to the horizontal. During the motion the skier is to be modeled as a...

Homework Statement An airliner of mass 300 tonnes is powered by four engines, each developing 15 000 kW. Its speed at take-off is 75 m(s^1), and it takes 11 minutes to reach its cruising speed of 210 m(s^1) at a height of 10 000 metres. Calculate the work done against air resistance during...

Homework Statement (a) When the displacement in SHM is one-half the amplitude A, what fraction of the total energy is kinetic energy? What fraction is potential? The Attempt at a Solution I tried finding a ratio of KE/t, where t=KE+PE and PE/t but I got answers that didn't...

Homework Statement A 0.25 kg object is suspended on a light spring of spring constant 49 N/m. The spring is then compressed to a position 15 cm above the stretched equilibrium position. How much more energy does the system have at the compressed position than at the stretched equilibrium...

HI! Also: I have 1-d electron gas in tight banding model with included interaction between electrons of same spins V_{\uparrow}=-N_{\uparrow}U where U > 0, \sigma=\pm1 is spin up or down, and pauli interaction with outside field B is included. I have to calculate the total energy of gas at...

In deriving the chemical potential and also in discussion of intensive properties chemistry books will often do something like this. Say you have a gas and liquid isolated in a container, the total internal energy is equal to the energy of the gas plus the energy of the liquid. Why? I would...

Homework Statement C=epsilon(subscript0)L[[x+0.6L*epsilon(subscript1)+(0.4-x)epsilon(subscript2)]/d] calculate the total energy stored in the capacitor, as a function of x [4 marks] Homework Equations U=0.5C*V^2 The Attempt at a Solution I don't know what I am supposed to do...

What is the difference between the Hamiltonian operator and the Total energy operator? If both is used when working with total energy, why are there two different operators?

Homework Statement given a wavefuntion \Psi = (1/sqrt50) (3\mu1 + 5\mu2 - 4\mu3) what is the expectation value of the total energy? My thoughts were to calculate <\Psi|\hat{}H|\Psi> but the previous part to the question asks for the probability of each outcome(which I know how to...

In an oscillating LC circuit, L=25 mH and C=7.8 x10^-6 F. At time t=0 the current is 9.2 mA, the charge on the capacitor is 3.8 x 10^-6 C, and the capacitor is charging. What is the total energy in the circuit? I know I just need to do Ub+Ue=U, but here is my question. Are L and C constant...

Homework Statement The explosive fusion occurs in several steps, but the ultimate result is that carbon is fused into nickel Assuming that the entire white dwarf is carbon that fuses to nickel, show that the energy released in the explosion overcomes the gravitational potential energy, thus...

1. Helo all, A horizontal force of 80N acts on a mass of Kg resting on a horizontal surface. The mass is initially at rest and covers a distance of 5m in 0.92s under the action of the force. Assuming there are no energy losses due to air resistance and therefore that the acceleration is...

Homework Statement A student spends part of her day walking between classes or for recreation, during which time she expends energy at an average rate of 280 W. The remainder of the day she is sitting in class, studying, or resting; during these activities, she expends energy at an average rate...

Hi. How would you calculate the total electric potential energy of a battery containing two cells (just an example), with for instance 20 V (cumulative, if cells are in series) and runs on a 60 A circuit. Is it required to have the charge of the battery to calculate total energy in joules...

Homework Statement Beginning with the kinetic and potential energies of two objects with masses m1 and m2, show that the total energy of a binary system is given by: E=\frac{1}{2}\muv2 - G\frac{M\mu}{r} Homework Equations The one given K =\frac{1}{2}mv2 U = G\frac{Mm}{r} The...

Homework Statement "The numerator of this fraction: \overline{E}=\frac{\int \! E N(E)D(E)dE}{\int \! N(E)D(E)dE} (N(E) is the number of particles in an energy state, D(E) is the density of states) is the total (as opposed to the average particle) energy, which we'll call U_{total} here...

Homework Statement Homework Equations P = IV The Attempt at a Solution Part 1 For the first part I solved P = IV for the current flowing through the bulb to find that I = 0.5 A. I then divided 115 Ah by 0.5 A to get 230 hours. Now, I don't really understand what I did...

Homework Statement The voltage at terminal a relative to terminal b of an electric component is given by v(t) = 20\cos(120\pi t) Volts and the current into a is i(t) = -4\sin(120\pi t) amps. Find 1) the total energy that flows into component from time t1 to t2 and 2) in particular find the...

Homework Statement Calculate the total energy of a geosynchronous satellite (one that orbits over a fixed spot) with a mass of 1500kg, orbiting Earth at a height of 325km with an orbital speed of 5000m/s Homework Equations ET=Ek+Ep Ek=(0.5)(m)(v)^2 Ep=(m)(g)(h) The Attempt at a Solution...

Homework Statement A 12Kg mass udnergoes simple harmonic motion with an amplitude of 10cm. If the force constant for the spring is 320 N/m a) Calculate the total energy of the mass spring system. b) Calculate the maximum speed of the mass c) Calculate the speed of the mass when it is...

First of all this is not a HW question, I already "handed" the assignment in and its graded There was this question on my assignment, it asked questions off of a graph that had distance on the x-axis and energy on the y axis. The potential energy was a curve, and basically took up the entire...

I can't seem to get this started in the right direction. Any help is appreciated. As part of a treatment program, a patient ingests a radioactive pharmaceutical containing P32,15, which emits beta rays with an of 1.50. The half-life of is 14.28 , and the initial activity of the medication...

Homework Statement A flyball governor has an angular speed of 8.10 rad s^-1. Find the total energy supplied to the flyball governor in order for it to reach this angular speed Homework Equations Kinetic energy=rotational energy+translational energy translational energy=(1/2)m*v^2...

Homework Statement The displacement of a mass m = 0.01 kg is x(t) = 0.25m sin(62.83t/s − 0.785398) Find its amplitude, its total energy, and its speed at t = 0. Homework Equations E = Av^2 + Bx^2 x = Asin(wt-theta) The Attempt at a Solution i use that above formula to...

Just finished reading Hawking's 'The Grand Design' in which he appears to culminate in saying the Universe was spontaneously created by some sort of quantum mechanical process. He also comments that this is perfectly allowed if the total energy of the Universe is zero, suggesting that...

Homework Statement Suppose you start with two identical finite isothermal spheres, each with initial mass Mi and initial circular velocity vi, that are at rest a distance d apart. What is the total energy of this system? Hint: Consider the total energy for each one in isolation from part...

Homework Statement If a question asks to calculate total energy of an object that does have a horizontal velocity (constant, air resistance ignored), and it is at it's highest point so it's vertical velocity is zero. I need to know how you'd calculate the total energy of this object...

Is it possible to have negative total energy?

Homework Statement Black body radiation inside a cavity at temperature T may be thought of as a gas of photons with an energy distribution given by the function n(E) given by n(E)dE = A [E^2 / (e^(E/kT) - 1) ] dE Where A is independent of E and T. (k is Boltzmann constant) The...

Homework Statement The weight of a satellite in a circular orbit round the Earth is half of its weight on the surface of the Earth. If the mass of the satellite is 800kg, determine (i)the altitude of the satellite (ii)the speed of the satellite in the orbit (iii)the minimum energy required...

Homework Statement A)Show that for a non-frictional, simple linear pendulum (Sin(theta) ~ theta) the total energy of the pendulum (K + U) or kinetic plus potential is given by E = (1/2) m l^2 (d(theta)/dt)^2 + (1/2) mgl (theta)^2 and therefor E = (1/2) mgl(theta0)^2 theta0 =...

LC circuit! Homework Statement A 550 microfarad capacitor is connected across a 1.35 H inductor. At a certain time, the charge on the capacitor is zero and the current is 0.362 A. How much later will the capacitor charge reach its peak? What's the total energy in the circuit? What is...

hi, the following question is extremely important so please reply! in an atom, the energy levels of the electrons are negative and the velocity of the electron increases when the energy decreases. however, this cannot be the total energy(in relativity) because it does not includes the...

Homework Statement We have a system with N particles with masses m1, m2, ... mN and electrical charges q1, q2, .. qN that interact electrostatically. We assume these interactions are instantaneous. Construct the formula for the total energy and show that this is conserved. The Attempt at a...

How to determine the total energy of matter in the universe Hi all, while looking at a table of order of magnitudes of energies in nature, I just realize that I really don't know how to determine the total energy contained in the universe (near 10 to the 69). Can someone get this number...

Hi, a question at work popped up and it's been too long since I went to school :p The total energy [Wh] required to heat the system to temperature T is given by f(T)=1.28T. The effect [W] applied to the system is given by g(T)=378-3.16T. How long does it take to heat the material to say 80...

can we imagine that momentum is the total energy stored in the body at a particular velocity?if not then why?

Homework Statement A rollercoaster cart mass = 55kg velocity = 5m/s height = 5m what is the total energy that the cart has at this position? Homework Equations would s=d/t be relevant? The Attempt at a Solution already calculated gravitational potential energy: GPE = m*g*h =...

Homework Statement Calculate the total energy of a 2kg mass that is undergoing simple harmonic motion with an amplitude of 1cm and and frequency of 16Hz. Homework Equations ma = -w^2x The Attempt at a Solution The first thing I thought was using the general solution of x(t) = A...

Homework Statement I am trying to derive the total energy for an n-dimensional linear (Hookeian) spring-mass damper system and show that the total energy is either decreasing or constant. Homework Equations 1D spring-mass damper equation n-D spring-mass damper equation The Attempt at...

Homework Statement Derive an expression for the total energy required to asemble a sphere of charge corresponding to a nucleus of atomic number Z and radius R. Assume the nucleus is a sphere of uniform volume charge density \rho Homework Equations \rho = mass / volume = 3Am / 4*pi*R3...

2 electrons in box, "hard" walls, total energy E. Say we place 2 electrons inside an empty 1m cubed box with very "hard" walls, the electrons can penetrate only a very small distance into the walls of the box. Let us say that any photons produced by the scattering of the two electrons stay in...