Mass Definition and 1000 Threads

Hi to everybody! Please: can you help with this problem? A conductive disk with a radius a = 20 cm, with negligible moment of inertia, rotates around its horizontal axis. The disc region around the radius is inserted in a magnetic field B = 0.75 T perpendicular to the disk itself. A mass is...

So I have sort of a conceptual question about the big bang and gravity. Imagine yourself in a universe, in which existed about the number of particles/energy in a 3X3 metre room at any given moment. This universe has the same laws of physics, constants and is identical in every way to our...

Homework Statement What is the mass of the block? Given: friction less surface, velocity at each marked point, distance between points 1 and 2, spring constant l = 7 N/m Homework Equations F=ma Kinematic equations The Attempt at a Solution I tried to solve for a in m = F/a in order to find...

A 50.0-kg male dancer leaps 0.32 m high. (a) With what momentum does he reach the ground? I know that to find momentum the equation is P = mv, but I only have the mass and distance. I have tried finding the time (D = 1/2at^2) and later used that time to find the velocity (v = d/t). I later used...

I just read a book by nuclear physicist Carlo Rovelli on the subject of "Time" and he says that 'entropy' is the only non-reversible process in the basic equations of physics, and he believes time and entropy are related (if I understand him correctly). So this started me thinking on entropy...

Homework Statement Unbalanced meter stick has hanging mass of 100g at 0m point. I then moved fulcrum to balance it and it was balanced at the 0.33m point. (The hanging mass and 0m point is on left side) I want to get the mass of the portion of the meter stick on right side, but I am confused as...

Homework Statement The vector position of a 4.00 g particle moving in the xy plane varies in time according to 1 = (3i+3j)t +2jt^2 where t is in seconds and is in centimeters. At the same time, the vector position of a 5.95 g particle varies as 2 = 3î − 2ît^2 − 6ĵt. Determine the acceleration...

Homework Statement A car has a mass of 1500kg. If the driver applies the breaks, the maximum amount of friction force that can be applies without skidding is 7000N. If the car is traveling at 25m/s, what is the shortest distance the car can stop safely? Homework Equations I'm assuming it has...

Hi, my name is alexander, i am student from Institute of radioprotection and dosimetry (IRD). My project is calculate MGD (mean glandular dose) from womans with augmented breast. i am having dificulties to calculate Kerma in air with mcnpx. I drew a block of air above the breast, i am using the...

Homework Statement The lab: Centripetal Force Lab a Rubber stopper is moving in a horizontal circle at a constant radius and it is attached to a string where at the bottom, there is a mass where the mass is 100g, 150g, 200g, 250, and 300g (can see image attached) from the lab, I collected...

I am trying to teach myself Physics, so I can use it in engineering for my own devices. The project I am working on right now is a very simple spring based launcher. This is frustrating me to no end. Here is my objective. I want to lunch a golf ball about 10 or so feet. I know that I need to...

Has anyone listed the actual experimentally measured masses of isotopes ? I find only the mass excesses listed. Why?

Hi community, I've been looking at solutions for mass spring shm (undamped for now) ie that x = Acoswt and x = Bcoswt work as solutions for dx2/dt2 = -(k/m)x and that the general solution is the sum of these that with a trig identity can be written as x = C Cos(wt - φ) where C is...

Hello! I am reading Schwarz QFT and I reached the mass renormalization part. So he introduces, after renormalization, a physical mass, defined as the pole of the renormalized propagator, and a renormalized mass which can be the physical mass, but can also take other values, depending on the...

<Moderator's note: Moved from another forum and thus no template.> I have a project from my Mechanics class which consist on building the system on the picture. It has a spring, cable and a protractor. I have to do an approximation of the mass and weight of the object that is put in the...

Homework Statement The question is similar to last week’s, except that we will consider how friction may damp the oscillation with time. A block with mass m shown in the drawing is acted on by a spring with spring constant k. The block is pulled distance [x[/0] from equilibrium position (x=0)...

Homework Statement A man pushes a 50 kg box up a 20-degree ramp at constant velocity. If the pushing force is parallel to the ramp, and the coefficient of friction is 0.4, how much force is he pushing with? Homework Equations u=Fs, max/Fn Not sure if this equation is needed. The Attempt at a...

Homework Statement A spigot pours beans onto a scale platform. At a time t = 0.0 sec, the spigot is opened and beans begins to pour out (with initial velocity 0) at a rate of 1.00 kg/sec onto the platform from a height of 10.0 m above. (a) At t = 10.0 sec, what is the weight of beans on the...

I am enrolled in a course related with physics, and we have a table of equivalencies of units to get the right units of frequencies. Stiffness Mass Frequency tonf/m ton.s^2/m rad/s kN/m ton rad/s N/m kg rad/s kgf/m...

Hi, If I find out the tangential force on the bob at position 1, it turns out to be m*g*sinθ. From this if I find out acceleration by dividing this equation by m, I get only g*sinθ. Does it mean the max acceleration of pendulum has got nothing to do with its length or mass but theta?

Given an unconstrained (suspended without contact to anything) electric motor with its own power in total has mass m1 Given the motor shaft is connected to a payload of mass m2 If m1>m2 then: m1 no-spin + m2 spin If m2>m1 then: m1 spin + m2 no-spin What happens at the unit ratio (m1/m2 = 1...

Homework Statement In the figure above a block of mass m is connected to a block of mass M > m by a string. Both blocks sit on a smooth surface with a coefficient of kinetic friction µk between either block and the surface. In figure a), a force of magnitude F (large enough to cause both blocks...

What happens to an object when you negate the Higgs field to give an object zero mass? Does it behave like light and travel instantly without force (or is there a gap here?) I heard if you took away mass from something like a baseball it would just float. How does this reconcile with the...

Homework Statement I'm perpetually confused keeping track of the energetics of a nuclear reaction and I broke down my conceptual questions into the following parts statement a-In a fission reaction, the two medium sized daughter nuclei each have more binding energy per nucleon than the original...

Hello, Assuming that dust is formed by silicates with Mg and Fe. What is the largest possible silicate dust-to-gas ratio in mass?

As I understand E=m*c^2 you can create mass from energy In my imagination that means, that if you create a high enough energy density, then you will create mass equvilant to that energy. (with some loss i imagine) That understanding have made me think, could we, in theory, create enough energy...

The Question is posted as a photograph with a. little change. One of the mass in the photo is equal to '2m' rather than 'm'. Now the block won't stop consecutively. How would we approach the question?

Hi Everyone! There is a type of CO2 laser cutter power meter on the market (Product link removed) The meter uses a block of black anodized aluminum bonded to the end of basically a mechanical meat thermometer, and has a zero adjustment on the back of the face to set the base temperature to...

Homework Statement A rigid cylinder of radius ##R## and mass ##\mu## has a moment of inertia ##I## around an axis going through the center of mass and parallel to the central axis of the cylinder. The cylinder is homogeneous along its central axis, but not in the radial and angular directions...

In Newtonian mechanics, both gravitational mass and inertial mass is m. This principle is known as the principle of equivalence. However, I heard that in Relativity, gravitational mass is γm instead of m because total energy of the particle is γmc2. But in special relativity, it is widely known...

Homework Statement In the ammonia (NH3) molecule of the figure, the three hydrogen (H) atoms form an equilateral triangle, with the center of the triangle at distance d = 9.40 ✕ 10^−11 m from each hydrogen atom. The nitrogen (N) atom is at the apex of a pyramid, with the three hydrogen atoms...

Homework Statement The coefficient of static friction is 0.604 between the two blocks shown. The coefficient of kinetic friction between the lower block and the floor is 0.104. Force F causes both blocks to cross a distance of 3.44m, starting from rest. What is the least amount of time in which...

Homework Statement [/B] A particle of mass 'm' is initially in a ground state of 1- D Harmonic oscillator potential V(x) = (1/2) kx2 . If the spring constant of the oscillator is suddenly doubled, then the probability of finding the particle in ground state of new potential will be? (A)...

Hello, Can you tell me please the mass flow rate of hydrogen and oxygen per unit of area of electrodes in fuel cells? Or if you have information on the mass flow rate of hydrogen and air per volume of fuel cell stack? I understand this may vary, but I am looking for publications or other...

Homework Statement Hello! I have a physics problem that I can't solve. I'm supposed to describe how I can calculate the mass when knowing the µv (I don't know the english term but I'm guessing friction...something (friction when the object is not moving)). You are allowed to use a dynamometer...

What do people think of Fulvio Melia's argument for the necessity of "zero active mass" in FRW cosmologies? (i.e. the overall equation of state must be ##\rho+3p=0## at all times) Here is a link to an interesting lecture video: Here is a recent paper: https://arxiv.org/abs/1807.07587

Homework Statement A pressurised air tank supplies compressed air to an air engine. When the air engine is not running the absolute pressure in the tank is 300 bar and the temperature of the air is 60°C. Calculate: (a) The temperature of the air in the high pressure air tank when the air...

The Wikipedia entry on "White dwarf" has a table listing the densities (in kg/m3) of various objects/substances, and states that an earth-mass black hole has a critical density of 2 x 1030, about 13 orders of magnitude denser than atomic nuclei. Has such an enormous density been calculated...

Hello everyone. I'm currently working on NS mass relations and trying to plot a curve with predicted masses-radii and observations on NS. There are some free data at this website: http://xtreme.as.arizona.edu/NeutronStars/index.php/neutron-star-radii/ . I downloaded the .tar file and tried to...

After reading some classical physics I learned that the entire physics is actually studying the combination of 3 quantities mass, length and time. Anything in the universe is just the combination of mass and length and time. And why i say that? Because if you notice the formulas that the...

(This is to check my understanding ) I gather that gravity being a space-time distortion is thought to affect everything - mass, radiation, whatever - and can be thought of as an accelerational effect. If it is an acceleration, even entities with mass = 0 are accelerated (?). So is there any...

1. Vo Mass=m 2.So we tried two ways of doing this, one is by taking the y component of the i itial velocity and using that and the other by using the component of its weight parallel to the initial velocity.They give conflicting answers. For the left one it turns out to be t=Vosinθ/g But for...

So the gravitational field has energy and momentum, and so you can never have a spacetime with an energy stress tensor set to 0. Is this like a constant then? that you can calculate for a portion of spacetime with no "stress energy tensor"?

Why wouldn't a brown dwarf grow in radius if it started to gain mass?

I did look it up , but couldn't find anything that explains this in a simple manner.

Hey, first of all I apologize if this isn't the right thread because I was confused of where to put this. Recently I've learned about Quantum Field Theory and the Higgs Field. I kind of understand why the Higgs Field gives particles mass. From what I have learned it's because the field is...

Homework Statement A mechanical servo-mechanism comprising of a movable piston-cylinder within a vertical cylinder operates based on a venturi contraction in a horizontal 350mm diameter pipe that delivers a fluid of relative density 0.95. The upper end of the 100mm diameter vertical cylinder is...

Hey, I'm a student who has to complete a written assignment for physics. I chose to launch water rockets and investigate the effect of volume on the range. I am trying to also come up with a mathematical model however I am struggling to understand an equation I found the following equation to...

1) space is expanding at an increasing rate, therefore things are getting farther from each other and therefore increasing in velocity. 2) the faster an object moves relative to another, the more mass it has 3) supermassive objects can turn into neutron stars, black holes, etc. Therefore, will...

Homework Statement Find the mass of photon in motion. Homework Equations E=hf p=hf/c The Attempt at a Solution I just started studying modern physics and am aware of the above two equations. However equating E to 1/2mv^2 gives a different (wrong) answer while equating p to mv gives the...