Mass is both a property of a physical body and a measure of its resistance to acceleration (rate of change of velocity with respect to time) when a net force is applied. An object's mass also determines the strength of its gravitational attraction to other bodies.
The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity, but it would still have the same mass. This is because weight is a force, while mass is the property that (along with gravity) determines the strength of this force.
This question stems from one of the recent homework threads. I'm familiar with the derivation given here regarding mass accretion and ejection, where the general idea is to define a system around body and all of the incoming/leaving mass so that we can once again apply NII to the whole thing.
I...
Hello,
I've got to rationally analice the form of the solutions for the equations of motion of a simple pendulum with a varying mass hanging from its thread of length ##l## (being this length constant).
I approached this with lagrangian mechanics, asumming the positive ##y## direction is...
The question, "why didn't the emerging universe collapse into a black hole" has been answered in other forums. Though I am not sure I understand the reason. But it got me thinking. Is it particularly stupid to ponder whether a black hole has a maximum possible mass? Or rather a certain mass...
I can easily do the second problem if only I knew the answer to the first. I am just not sure how I would go about figuring out if the spring has mass or not. And if it does, how would I calculate that mass?
1.
How will the motion of M be? I assume wire S is inelastic so will M move downwards but not in straight line? (I mean M moves downwards but because the left side of pulley is connected to S, it will be static and the right side of pulley can go down along the extension of the spring so its...
Hi, I'm looking for help making a graph/model for evaluating the "bounce" of a mass behind a spring that collides with a wall. The setup would include one simple spring mass system that is attached to a wall, and another wall which is closer to the mass than the spring's free length. The mass is...
Wikipedia says this about the missing mass of a reaction:
I wondered where such an expression is coming from? The invariant mass of a system ##M##, in natural units, satisfies $$M^2 = \left(\sum E \right)^2 - ||\sum \mathbf{p}||^2$$ If anything, then the "missing" mass (which they also...
hello
Witch of these are certain sentences?
a-\dfrac{e}{m_e}>\dfrac{H^{-}}{m_{H^{-}}}\cdot{1000}
b-\dfrac{e}{m_e}>\dfrac{H^{+}}{m_{H^{+}}}\cdot{1000}
The first accurate measurement of e/m was made by english physicist J.J. Thomson in 1897, who demostrated that the quotient charge-mass of the...
When two BHs collide the resulting single BH bulges and contorts until it settles down to a stable state.
1) Does this mean that during this 'settling' period the mass internal to the merged BH is not (yet) a singularity, but instead two 'singularities' spinning down around each other in...
I know that it will probably execute something similar to circular motion. I thought of conserving momentum but I think there is an external force being applied due to the impulse which will prevent me from doing so.
I know that once I find the tension it would become very easy to find the...
Since 2nd pulley accelerates downward with the same acceleration of m1, and because the string around pulley has a constant length, it must be that a2=−a1+ar and a3=−a1−ar, where ar is the relative acceleration between the pulley and m2.
From the above 4 equations, we are supposed to determine...
I was thinking, what would be the consequence if we wouldn't adopt the ro in the infinite, and i conclude that it would just irritate the accounts, with one constant more, am i right? Once what matter is the diference between the U, and no the U infact.
This is a past exam Q, I don't have the attached pressure enthalpy diagram.
Q = 120kW
Cp = Refrigerant enthalpy = I've looked this up, for ammonia enthalpy = 35.06 kJ / mol
T2 = 5 degrees C = (5 deg C) (1100 kPa/300 kPa) = 18.33 deg C +273.15 K = 291.48 K
T1 = 2 degrees C = (2 deg C)(1100...
What does it mean that the relationship between mass and weight is constant and proportional?
I think I don't get it yet. The weight depends of mass, but at the same time depends of gravity, so if mass increase, the weight so does. But if we're on Earth we know that"g" has a value, therefore...
Assumptions:
1) The minimum stellar mass in this cluster is 0.1M⊙
2) The maximum stellar mass in this cluster is 150⊙
First calculate the local stellar density constant (ξ0) for this cluster using eq 1:
Having rearranged this equation and using the limits of the minimum and maximum stellar...
Let’s say we have a boat whose longitudinal axis is the y-axis (which goes into the screen in the figure below) standing upright in a still water .
##S## is the Center of Mass of the boat and ##C## is the Center of Mass of the displaced water.On ##S## lies the force ##\mathbf W##...
I'm specifically referring to these slides Supersymmetry - Holomorphy on pages 7 and 8.
Why is the mass of the superfield defined as \frac{\partial^2W}{\partial \Phi_H^2}
and why are the equations of motion \frac{\partial W}{\partial \Phi_H}= 0 and not \frac{\delta \mathcal{L}}{\delta \Phi_H}= 0?
I know that from the given problem, I need to find the expression for Kinetic energy,
KE = 1/2 m [r(dot)]^2
and Potential energy,
PE = 1/2 k r^2
So L = 1/2 m [r(dot)]^2 - 1/2 k r^2
Hence H = 1/2 m [r(dot)]^2 + 1/2 k r^2
I assume that the fixed length r0 is provided to find the value of end...
We know that the energy levels for electrons surrounding nucleus are quantized , only coming in discrete levels.
When I see the standard model of elementary particles table I notice specific masses for each of the particles whether they be quarks or leptons or bosons like the higgs.
I know that...
(I know how to solve the problem, that's not what I am looking for.)
I have a problem with how I ought to understand the moment of inertia. The only torque I see applicable on the wheel is that of the tension, and so I think that ##I## should be ##m_{\text{point}}R^2##, without including all the...
a) In the rough approximation that the density of the Earth is uniform throughout its interior, the gravitational field strength (force per unit mass) inside the Earth at a distance r from the center is gr/R, where R is the radius of the Earth. (In actual fact, the outer layers of rock have...
[Moderator's note: Spin off from previous thread due to topic change.]
Just as an aside and not related to the OP, would a real particle with negative mass inside the event horizon follow the runaway motion? Would it be ejected?
I know that if they had the same density they would have the center of mass at 1,5 m. But now that they don't the center of mass will be shifted towards the part of the rod with higher density. they will have their center of mass where they
have equal mass
p1*v=p2*v
now i don't know how to...
A mass (M) is attached to a spring (K). Mass moves in a one dimensional plane (horizontally)
1) If mass M is initially at x=0, what is the minimum Work required to bring it to x=x0 ? PE ?
2) M is released from x=x0, PE when x=xo/2 ? KE ?
3) PE when x=0 ? KE ?
4) PE when x=-x0/2 ? KE ?
5) What is...
Hey all,
I need a reality check and verification on some work I have been doing. I feel as though I might be too close to the problem now and am missing something about this. It's also been a few years since I studied physics at University, so I'm a little rusty.
Problem:
An initially...
I was talking to someone about the equilibrium of fluids and we reached at some stage where we had to prove that in an external field the translational forces add to zero along with moments (torques) should also add to zero. The first one was quite easy but during the discussion of second...
<work done a system>
a) w=5N*(0.4m)=2J
I think this is right, but
b) center of mass initial = ((0.5kg)(0.05m)+0.5kg(0.65m))/1kg = 0.35m
center of mass final = ((0.5kg)(0.45m)+0.5kg(0.4+0.1+0.3+0.25))/1kg = 0.75m
I'm not sure for this one... How can I calculate the displacement of the...
I'm finding it slightly tricky to just get a hold of where to start. I try $$\text{m}\text{s}^{-1} = \frac{c}{3\times 10^8}$$ If we then set ##c = 1##, that would seem to imply $$3\times 10^8 = \text{s}\text{m}^{-1}$$For ##G = 1##, I might also write $$\text{kg}\text{m}^{-3}\text{s}^{2} =...
Summary:: Specifically, how Earth and life on it would have evolved if our planet was twice as massive but with the same composition of building elements?
Could humans or sentient, upright walking creatures appear in the evolutionary scale in a twice as strong gravitational field? How that...
Hello All:
i remember (and saw ) that the SARS-ncov-2 layers have hydrophobic and hydrophilic properties
few weeks ago i was reading about forth flotation and it is a method to separate metals , but on low temperature could we use it to separate the spike protein and mix it with immune cells...
Can someone simply explain to me what are the time crystals? What are they built from (matter, do they have mass)? I cannot find a clear explanation of them. I just know that ordinary crystals are 3d, time crystals - 4d.
A particle of mass m is in the ground state on the infinite square well. Suddenly the well expends to twice it's original size (x going from 0 to a, to 0 to 2a) leaving the wave function monetarily undisturbed.
On answering, for ##\Psi_{n}## I got ##\Psi_{n}## = ##\sqrt{\frac{1}{a}}...
time/#periods=T= 30.58/10= 3.058
Displacement=.6m
T=3.058
I tried to rearrange hooke's formula to k=f/x but f=mg and I don't have mass.
Using the period formula is also hard because T=2π( √m/k) and I have neither m or k :/
Please help thanks.
Hi guys,
so I am struggling on the Standing Waves concept. I understand that these are waves that move in place but I don't know how to attempt this problem. Can someone set me on the right track?
Now, if I recall correctly, lighter objects with smaller inertia do go faster in terms of acceleration and farther than objects with heavier mass or inertia when the same force is exerted on them. But what about same accelerations? If a light object and a heavy object were to undergo the same...
I want to know between which two quantities of energy, momentum, and mass there is an uncertainty principle going on. Can I measure any two of those at the same time? If yes, which ones?
Thank you in advance
The term “negative mass” gets puts forth occasionally, and it’s definitions can sometimes be unclear.
the topic I’m interested in is particles which have both positive inertial mass and negative gravitational mass.
So far, what theories do physicists have of speculating on the existence of...
I had started off by equating the magnetic force to the centripetal force, to find the mass of a single ion. Then calculated the mass of what 1 mole of that ion would weigh to identify what the ion is
Hence the answer would be nitrogen (option C) as 1 mole of nitrogen weighs 14g
Would this...
A known force is doubling (egal) over a known distance, accelerating a mass.
How do I calculate the final velocity of the mass at the end of the known distance , when the mass has doubled? I don't know the time.
The mass is accelerated from 0 meter and from 0 velocity.
Sean Carroll gives the Planck's set of four dimensioned quantities: Planck's mass, length, time and energy. I wanted to compare them with actual things.\begin{align}
m_p=\sqrt{\frac{\hbar c}{G}}&=2.18\times{10}^{-8}\rm{kg}&\rm{{10}^{7}\ E. coli}\phantom {100000000000000000000}&\phantom...
Hello everyone!
Let's say that you were to attempt to go as fast as possible on a spaceship with the mass of an average car in an absolute perfect vacuum. What I am wondering is, that if you were to reach a certain speed, and stop applying energy to this imagined spaceship, would the spaceship...
Figure 4 shows three point masses glued to the vertices of a massless triangle of side L=2.0 m. Two of the massess are m=0.75kg and the other mass is twice that value, as shown in the figure. The device is allowed to rotate about point A in a verticle plane about the centre of the larger mass...
The answer is 127.04g. I’m getting close but can’t get the answer.
Using 9.81 for gravity, the force where the balance is is 2.10(58146)N
As it is balanced
2.10N x 0.29m = W x 0.50m where 0.50 is the centre of mass
That gives W = 1.22N
= 124.5g?