What is Total energy: Definition and 232 Discussions
In physics, energy is the quantitative property that must be transferred to a body or physical system to perform work on the body, or to heat it. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement in the International System of Units (SI) of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of one metre against a force of one newton.
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.
Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.
Living organisms require energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the Sun and the geothermal energy contained within the earth.
Homework Statement
A particle, observed in a particular reference frame, has a total energy of 10GeV and a momentum of 6GeV. What is its mass in units of GeV/c^2?Homework Equations
I used p=\gamma mv
and
E=\gamma mc^2The Attempt at a Solution
So I divided the above equation for P by the...
Homework Statement
You have an ideal two-state paramagnet (DPPH) with mu=mu_B (bohr magneton). There is a magnetic field of strength 2.06T, and the minimum temperature was 2.2k. Calculate the total energy of the system as a fraction of its maximum possible value.
Homework Equations
from...
Homework Statement
The problem I am doing is problem 1.55 in Schroeders Intro to Thermal Physics. Unfortunately, I have to come here for help a lot because the office hourse are not until after the homework is due...In any case, the first part of the question was to show that the potential...
Homework Statement
X(t) = Xe(t) + Xo(t) where Xe(t) = (1/2){X(t)+X(-t)} is the even part and Xo(t) = (1/2){X(t)-X(-t)} is the odd part of the signal. Let X(t) be an energy signal with energy 5 Joules. Suppose the even part of X(t) is Xe(t) = exp(-|t|). Determine the energy in Xo(t)...
Homework Statement
Calculate the total energy of a geosynchronous satellite (one that orbits over a fixed spot)
with a mass of 1.5 x 10^3 kg, orbiting Earth st a height of 325 km with an orbital speed of 5.0 x 10^3 m/s.
Homework Equations
Ek = 1/2 mv^2
Ep = mgh
Fg = Gm1m2/r^2
or
PE...
I'm confused as to what scientists agree on, since I've read many answers. Is the total energy of the universe less than, equal to, or greater than zero?
Is the universe open, flat, or closed? (I'm not sure if this is the exact same question as the previous)
Is this a debate within the...
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...
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
B=Boexp[-(kz-ωt)2)] i(hat)
Calculate the electric field associated with the above magnetic field pulse.
Calculate the Poynting vector for the EM field and the total energy per unit area.
Use Maxwell's equations in vacuum and assume electric potential is zero.
Homework Equations...
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...
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
(a) A certain battery runs a toy truck and becomes partially discharged. In the process, it performs a total of 117J of work on its immediate surroundings. It also gives off 3.0J of heat, which the surroundings absorb No other work or heat is exchanged with the surroundings...
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 is...
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...
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...