What is Conservation: Definition and 999 Discussions
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.The conservation ethic is based on the findings of conservation biology.
TL;DR Summary: .
An electrone moves in a magnetic field ##B(\vec r)=g \frac {\vec r}{|\vec r|^3}##. Why does the conservation of the quantity $$\vec J=\vec r \times\vec p +eg\frac {\vec r}{|\vec r|}$$ mean that the motion is on the surface of a cone?
For this problem,
The reason why I am not sure whether it is a valid assumption whether momentum is conserved because during the collision if we consider the two masses to be the system, then there will be a uniform gravitational field acting on both masses, and a spring force that is acting...
I understand that conservation of motion comes from the action and reaction pairs of newton's third law. When it is triggered, two forces appear that cancel when analyzed as a system. My question is how is it that momentum is conserved if before the shot there was no force in the system and...
Hi.
Question as in the summary.
Spin has no obvious classical interpretation but it is often a conserved quantity and considered as some sort of angular momentum. What do you need to establish that spin is a conserved quantity? I'm finding references to situations where spin is not a...
So, I cannot for the life of me write a conservation of energy statement, when an object is lifted up by a force. So in my example there is a box on the floor with v = 0, and then a force of magnitude F, where F > mg, acts on the ball, now the net force is F-mg, and hence the work done is (F -...
I've already solved the orbital speed by equating the kinetic and potential energy in the circle orbit case.
$$\frac{1}{2}mv^2 = \frac{1}{2}ka^2.$$
And so $$v^2 = \frac{k}{m}a^2$$
Now when the impulse is added, the particle will obviously change course. If we set our reference point in time...
Consider a fluid flow with density ##\rho=\rho(t,x)## and velocity vector ##v=v(t,x)##. Assume it satisfies the continuity equation
$$
\partial_t \rho + \nabla \cdot (\rho v) = 0.
$$
We now that, by Reynolds Transport Theorem (RTT), this implies that the total mass is conserved
$$...
After trying to kinda get a picture of the field of play in quantum physics according to the standard model, a question came up. I tried to formulate the known bosons each as a particle transferring some property.
1. Photons transfer electric charge: the electromagnetic force gives attraction...
In Chapter 5.3, Ballentine uses geometrical arguments to obtain the initial magnitude of a hydrogen atom's bound electron momentum. How does equation (5.13) obtain? I tried to naively compute
$$p_e^2 \equiv \textbf{p}_e\cdot \textbf{p}_e = p_a^2+p_b^2+p_o^2 + 2\textbf{p}_a\cdot \textbf{p}_b -...
Question:
With maximum do they mean that the speed of the pions is the same as the proton and an antiproton? Otherwise there will be two unknowns, and if I use both relativistic-energy and momentum conservation equations I get difficult equations.
The statement of the problem is:
Consider a taut string that has a mass per unit length ##\mu_1## carrying transverse wave pulses of the form ##y = f(x - v_1 t)## that are incident upon a point P where the string connects to a second string with mass per unit length ##\mu_2##.
Derive $$1 = r^2...
I was wondering why energy of capacitor does not equal change in kinetic energy PLUS change in potential energy where potential energy is the change in the potential energy of the charges. I believe that should be so because energy conservation = change in kinetic energy plus change in potential...
In Dirac's "General Theory of Relativity", at the end of Ch. 25 (p. 47), right after deriving the full Einstein equation ##R^{\mu\nu} - \frac{1}{2}g^{\mu\nu}R = -8\pi\rho v^\mu v^\nu = -8\pi T^{\mu\nu}##, he makes a reference to the conservation of mass (Eq. 25.3):
$$0 = (\rho v^\mu)_{:\mu} =...
For this problem,
Why for part (a) the solution is,
Is the bit circled in red zero because since the putty is released at a very small distance above the rod it velocity is negligible?
Also for part (d) the solution is
I did a computation of the initial and finial kinetic energies of the...
The charge of an isolated system is conserved.
This implies the charge of the universe is constant.
This implies that charge can neither be created nor destroyed.
This implies that the net positive charge and the net negative charge of the universe are conserved. Is this right?
For this problem,
Is the length vector into or out of the page and how do you tell?
EDIT: Why must we use conservation of energy for this problem? I tried solving it like this:
##IdB\sin90 = ma ##
##IdB = ma ##
##v_f = (2aL)^{1/2} ##
##v_f = (\frac {2dIBL} {m})^{1/2} ##
Which is incorrect...
For this problem I was very confused whether conservation of angular momentum should be applied to the person, the swing or the person-swing system. It seems to me that there is no net torque on any of the three systems I listed above. However, it seems that the angular momentums of the three...
In the derivation of the conservation law of the conservation of mass, the flux on one side enters and the flux on the other side leaves the control volume. I presume this is due to the assumption that the volume is infinitesimally small and hence v(x,y,z,t) will not change directions...
Assume you have a two particle system, A, which has a mass and gravitational pull of g,
and B, an object with low mass,
The system starts at time 0 with the distance between A and B being 0, A being at rest and B having enough kinetic energy to move it a distance r away from A, until time t all...
The rotating ball should push the vehicle first to the right and once it hits the airbag - to the left?? Even if this works, how are you going to automate it and repeat it?
It isn't often that you see this many bold claims in a five page Letter, the abstract and citations of which appears below.
The conclusion I find most interesting is this Letter's conclusion that contrary to the current consensus understanding of the mathematics of the Standard Model (mostly...
If conservation of charge gets violated in future experiments, what would be the implications on relativity? I have some faint idea that this will cause photons to have non-zero rest mass, but does this affect special relativity at all? Also, does special relativity make conservation of charge...
Please help me to understand which ans is correct.
To determine the ##P2##.
$$
h_{LM}\ne 0
$$
Method 1：
$$dP=\frac{\partial P}{\partial x}dx+\frac{\partial P}{\partial y}dy+\frac{\partial P}{\partial z}dz$$
$$\phantom{\rule{0ex}{0ex}}\rho \overset\rightharpoonup{a}=-\triangledown p+\rho...
For this problem,
The solutions are,
However, how would we solve this without using the idea of conservation of string? Can we apply Newtons second law to each mass?
My working is:
Then apply Newton's Second Law to each pulley,
(Line 1)
(Line 2)
(Line 3)
(Line 4)
Many thanks!
So i was able to solve the angular velocity part but i don't know how to find the velocity of centre of mass . For the first part i simply conserved momentum about COM because if i consider the particles as a part of the same system as rod the collision are internal forces . I am mainly...
I found this article* about the behavior of quasar outflows in cosmology and how they can create a magnetic field.
In section 2.1.4., the authors say that when a quasar produces a "wave" or an outflow, the material will be emitted with energy coming from both the quasar itself and the Hubble...
-Solved for vf using equation 3 to get 20.0m/s (speed before explosion) then solved for the distance to reach the explosion using equation 4, to get 20.0m, which felt wrong having the same numbers but that may just be coincidence.
-Found the distance travelled of the lighter piece using 530m -...
I tried approaching this question like this:
F_N - mgcos(theta) = -mR(theta_dot)^2
and theta_dot = v/R since R is constant
F_N = m(gcos(theta) - (v - v_0)^2/R) (with v being final velocity and v_0 being the initial velocity from the impulse)
and then using energy conservation:
at t = 0: E =...
So i am tried to conserve momentum and use conservation of mechanical energy but won't there be psuedo force acting on the block if i am solving from non inertial frame ?. If i ignore the pseudo force and simply use C.O.M.E and include the K.E of the wedge and solve normally i do get the...
ConservationConservation of momentum
Energy
Energy and its consevation
Inclined
Inclined plane
Mechancis
Mechanical
Mechanical energy
Momentum
Non inertial frame
Plane
Translation
For the first part, the mass sits at rest on the spring, so it is at the equilibrium position and thus mg = kd
So, d = mg/k
For the second part, I assume the uncompressed spring position is 0. When the mass at rest at the top. Its KE and PE is 0. When the mass at distance D, the question said...
If energy is "not conserved" in General Relativity (or at least, it is difficult to define it) in the context of an expanding accelerating spacetime (like it happens in our Universe), are there any observations of deviations from the strict conservation laws in the evolution and formation of...
Hi,
I completely failed this homework. I mean I think I know what happen, but I don't know how to show it mathematically. The energy lost by the wave is used to oscillate the electrons inside the conductor. Thus, the electrons acts like some damped driven oscillators.
I guess I have to find...
I am trying to solve this two level (Schrodinger) equation as a function of time:
$$i\begin{pmatrix}
\dot{x}\\
\dot{y}
\end{pmatrix} = \begin{pmatrix}
0 & iW+dE_0sin(\omega t)\\
-iW+dE_0sin(\omega t) & \Delta
\end{pmatrix}\begin{pmatrix}
x\\
y
\end{pmatrix}$$
(I can go into more details about...
I have a wrecking ball with a mass of .5kg traveling at 3.03 m/s that hits a stationary block .9 meters high, weighing .06kg. I calculated the ball's exit velocity after it hits the block to be -3.00 m/s .
I calculated the final velocity of th block to be 4.2 m/s
Vf = Sqrt 2(g)(h) = sqrt...
This question was raised but not answered in a thread which is now permanently closed. Consider the local conservation of charge ##\partial_{\mu}j^{\mu}=0##. In quantum field theory it is valid as an operator identity, but operators as such do not have a direct operational (experimental)...
I already know the solution to this, all you do is set the height of the top of the trampoline to 0 and solve for initial velocity so the equation for the conservation of energy $$mgh_0 + \frac{1}{2}mv_0^2 + \frac{1}{2}kx_0^2 = mgh_1 + \frac{1}{2}mv_1^2 + \frac{1}{2}kx_1^2$$ becomes...
Hello there, I have tried the problem but don't get a different of 6g's as I am supposed to. I am not sure whether I interpreted the problem in the correct way, but I would love some feedback/hints on what went wrong in my solution, thanks in advance.
Solution:
SITUATION DRAWINGS + FBDS
so...
Many texts state that in an elliptic orbit you can find angular momentum magnitude as
$$ L = r m v = m r^2 \frac {d \theta} {dt} $$
I wonder if
$$ v = r \frac {d \theta} {dt} $$
is valid at every point. I understand this approximation in a circumference or radius r but what about an arc...
so I haven't looked at the solution yet, but I know that a 100% the velocity needs to be bigger, but analytically, I get a - sign instead of a + sign as you'll see at the final square root.
So for the first 15meters of the motion all you should know is that ##v_1 = 10.458 m/s##.
for the 2nd...
this is an easy problem but would it be possible to consider car-car system. What I did on paper was carsystem and because they have the same properties(mass en speed) multiply by ##2##
solution for car-car-earth system I assume is the following if it is possible?
solution for car-car:
law or...
We know that if we take two particles and assume no external force is applied then by Newtons third law total momentum gets conserved after collision. If we take three particles and there is collision between them and no external force then the momentum is again conserved for each pair like in...
If we have a ball with mass m dropped from a height h down to the ground, how come we can't set the conservation of energy equation just as the velocity of the ball turns 0.
mgh = 0
If instead the ball were moving with an initial velocity v, would the equation be
##mgh + \frac{1}{2}mv^2 = 0##...
If I consider only the freight car's mass and the mass dm that's added to the freight car as part of the system, then I get this answer:
https://ibb.co/QfKSqQ5
But if I consider the freight car's mass, the mass dm, and the locomotive car as part of the system (maintaining the locomotive has...
This is the catapult.
At equalibrium the spring is 0.09 meters in length.
When its fully stretched out its 0.225 meters long and I place a rock (0.205 kg) close to where my finger is on the catapult.
The catapult starts with this much energy because 1/2 * k * x^2
90.54 is the spring constant...
I was able to calculate the correct answer (given by a solution sheet), V=5.364 m/s, using the momentum impulse equation, P0+J=Pf. If this value is correct, however, I don't understand how energy is being conserved. The speed increases after the person bounces off the trampoline while the mass...