Relationship Definition and 999 Threads

Is there an astrophysical relationship between the how large a star's core gets and how large the star itself gets? Is it a simple linear percentage, or something more complex? For example, red dwarfs can fuse their entire hydrogen allocation, so the whole star is the core. But the Sun has a...

Homework Statement Homework Equations ##J=\frac{I}{A}## A=π r2 The Attempt at a Solution Since I is constant and the diameter is doubled , A2 = π (##\frac{2D}{2}##)2 A2 = 4 A1 J2 = I/(4A1) = J1 /4 → (E) Is my answer correct ?

Homework Statement A cylinder with radius ##R## and height ##h## which has a distributed charge on its surface with density ##\sigma## spins over its axis with angular velocity ##\omega##. If the cylinder has a mass density ##\rho##, find the relationship between magnetic momentum and angular...

Hi. I am currently working on an assessed science experiment write-up. The experiment is about whether or not if mass of a pendulum bob affect the oscillation time for a simple pendulum. Obviously, the answer is no but I am struggling to write a concise and accurate explanation to why this is. I...

What is the relationship of gravity to density? In black holes the cause of gravity is that the star shrinks and becomes dense. But Jupiter's gravity is more than the Earth's gravity, although its density is lower? Is the sun's gravity more than the Earth's gravity, even though the intensity of...

When the driver applies brakes its velocity starts decreasing and direction of acceleration will be same to the direction of velocity. Is this statement True of False? Please explain the true concept of this scenario. As far as I understand is that Velocity will start decreasing. But I am...

Homework Statement Is there a relationship between head acceleration and jump height say for a 5 foot 2 inches boy weighing 120 lb? Homework EquationsThe Attempt at a Solution I think there is a relationship between body acceleration into the floor before jumping, but wondering if there is...

I derived a relationship between frequency and tension of a string, accounting for tension's effect in the linear density of the string. So in a nutshell, the equation is more complicated and is in the form of f^2=aT^2+bT (f is frequency, T is tension, ab are constants involving the control...

Hello folks, got a question regarding cooling tower I will like to understand. I got some performance data from some cooling tower makers on the condition of how the cooling tower will operate at different wet bulb temperature. Assumeing flow and fan power is constant, what i observe was the...

In a PDF presentation on star formation that I'm currently reading, I ran into the following statement: "If we observe an increase in a star's temperature but without any changes in its luminosity, it means the star is shrinking (its radius is decreasing)" I'm having trouble understanding...

Homework Statement In a practical that we conducted, we were investigating the relationship between Launch height and the range (horizontal distance it travels) of a projectile. We launched a projectile from various heights and measured the horizontal range it traveled before reaching the...

In a projectile motion practical, we had to investigate the relationship between launch of projectile and the range it travels. Increasing the height will obviously increase the range. However, we are trying to understand why it does in a more scientific way. We already know that increasing...

Homework Statement In the figure shown, a prism ABC can be used to reflect a laser beam such as WXYZ. Determine the relationship between θB and θA Homework Equations Sin(c) = 1/(refractive index) The Attempt at a Solution To be honest I am not sure at all, I know that for total internal...

I know that magnets produce magnetic fields (due to internal currents within the magnet). I also know that magnetic fields cannot do work on particles. Given that, here is an apparent paradox I cannot fully understand: Consider a strong magnet and let us imagine bringing a small iron object...

Hi I have a problem dealing with rpm power and torque. I have a motor powering a gearbox which has a 20:1 ratio. The power and rpm are not an issue so i have not looked at those figures but the motor produces 240Nm of torque. Since it is a 20:1 gearbox, i have assumed the torque is 20 times...

A question about the Mach-Zehnder interferometer. My understanding is: If its two arms are equally long, there is destructive interference in one output and constructive interference in the other output. So, the intensity of light detected at the first output should be 0% and at the second...

Hi , i really have an important question , first Iam an Arabic girl so my English may cannot be perfect ! SO ,, we took the TORQUE lesson in school and i found it hard to understand , can anyone JUST gives me some steps to understand it . AND THANK YOU FOR EVERY ONE ..

How can I show that ##\int_0^\infty e^{-nt}\,t^{x-1}\,dt=\Gamma(x)\,n^{-x}\,## for ##x \geq 1\,##?

1.A rectangular steelbar of length subjected to tensile force of 80kN. Calculate the change in length if the width and thickness are (40 & 25)mm respectively. (E = 207 GN/m2). Homework Equations E= stress/strain stress = F/A; F =80kN strain = dL/L 3. I just want to know what to use for the...

For the material used in a heater plate to generate heat for example, for a given amount of power (say 4.5 kw) does the higher resistance of the material mean it will produce a higher temperature? Or is it the other way around?

I'm stuck with a solution to the vertical spring with a body suspended. The solution says that when the body's gravitational potential energy is decreasing, the spring's potential energy must be increasing. How is this correct? I understand the analysis leading to the result that the vertical...

I read in several places that if, for example, a point particle exhibits uniform circular motion about the z-axis within an osculating plane not equal to the x,y plane, then the angular velocity still points along the z-axis, even though the angular momentum does not (it precesses about the...

In Special Relativity, acceleration at high speeds causes time dilation and length contraction. Is it fair to restate this as; Acceleration at high speeds causes curvature of spacetime? In General Relativity, curvature of spacetime causes acceleration. Acceleration at high speeds causes...

Wiki suggests dielectric strength is temperature dependent, but I've yet to find any math supporting this. I found some math corroborating a relationship between conductivity and temperature, but whether or not there's any causality between conductivity and dielectric strength has eluded me. Any...

While polar molecule solved in solution, is this refers to ionizable molecule? Is it necessary or is it different things according the definitions?

Hello, I Have a non-Hermitian Hamiltonian, which is defined as an ill-condition numbered complex matrix, with non-orthogonal elements and linearily independent vectors spanning an open subspace. However, when accurate initial conditions are given to the ODE of the Hamiltoanian, it appears to...

Does an increase in Capacitance mean a decrease in voltage? Thanks!

In my experiment, I intended to find out how the change in the bar magnet drop height from solenoid affected the emf induced in the solenoid, however, I am unable to come up with an equation that shows a relationship between the two variables. I have thought of Biot-Savart law, but I do not...

<Moderator's note: Moved from a technical forum and thus no template.> I am trying to design and perform a physics lab. It needs to show the relationship between torque and angular momentum. I have gotten as far designing a 4" PVC coupling and have it on a ramp. I am not sure where to go from here.

I was answering the question, "Since electric potential is always proportional to potential energy, why bother with the concept of potential at all?" I answered that this is because Electric Potential Energy requires a test charge to calculate, Electric Potential is present without a test...

How would you calculate the induced magnetic field B at some distance R from a bar magnet, given the magnetic moment of a magnet? (In general)

Hello. I know this is a dumb question but I am just learning chemistry. Ok, for collision theory, atoms need a certain amount of energy to bond, because they need to break old bonds and form new ones. Makes sense But, at high temperatures, things become gaseous. At low temperatures, things...

Does the initial position of the plunger in the solenoid make a difference to the pull force it is subjected to? I mean in the default position how much % length of the plunger should be within the solenoid so that optimum force is delivered to the plunger when the solenoid is turned on? I see...

Hello everyone. Maybe you can help me with the following. In the case of the electron, is there any known mathematical relationship between anomalous factor and fine structure constant?

Homework Statement Homework Equations The Attempt at a Solution Why is the temperature of the first state is 133.52oC? If at 300kPa & 133.52oC, from the ‘Saturated water—Pressure table’, it would give vf=0.001073m3/kg, far different from the specific volume as stated in the question which...

Hi, Lately I've been reading about a lab exercise in which Planck's constant is estimated using LEDs. Every procedure I've encountered states that the energy of an emitted photon (and by extension the potential across the semiconductor's band gap) is equal to the threshold voltage multiplied by...

I didn't understand the following: The relationship between ##V_{CE} ## and ##I_C## is linear. In active region, even if the ##V_{CE}## increases, ##I_C## remains almost same for a given ##I_B##. So, how can the relation between the two can be linear? Can anyone tell me the utility of the...

// moved from general forum, homework template missing // Assuming that by the word "Work", work on the system is meant. Both heat and work is energy in transit. I think heat is work done by constituent particles of a system on another system in contact. Now the work done by us on a system...

Homework Statement Prove or disprove: Every translation is a product of two non-involutory rotations. Homework EquationsThe Attempt at a Solution :[/B] I am not sure if I got the right proof for the special situation: A translation is the product of two reflections with parallel reflections...

Homework Statement for isentropic process, which of the following is true about the relationship of temperature and pressure? (1): P2/P1=(T2/T1)^[γ/(γ-1)] (2): P2/P1=(T2/T1)^[(γ-1)/γ] where γ = 1.4 for air Homework Equations stated above The Attempt at a Solution I have found equation (1)...

Homework Statement How to prove the correlation between launch angle (<45°) and horizontal displacement. Independent Variable: Horizontal distance Dependent Variable: Launch Angle (Important) Controlled Variable: Firing velocity [90 m/s] Another problem is, with the data that I have...

Hi everyone, I would like to know how to calculate the diameter of a pipe when we know the desired mass flow, the gas type, and the pressure at both end. I have these requirements : Gas : O2 Molecular weight : 0.032 [kg / mol] Desired mass flow : 0.32 [kg / s] Pressure in the gas tank : p1 =...

Homework Statement After plotting a graph with frequency (f) of a wire on the y-axis and tension (C-Clamps) on the x-axis, a root curve was obtained. If the trend of the line is maintained, does it pass through the origin? Should it? Note: graph attached Homework Equations f is proportional...

Homework Statement An experiment was conducted to determine the relationship between metre-stick projection from a table (L) on the vertical depression of the free end (y). Using the collected data, graphs had to be plotted until a linear relation was found, and the equation of the line had to...

Just to check my understanding: -The glass will only break when the sound is at the resonant frequency of the glass. -This creates standing waves in the glass. -The glass will only shatter if the sound is at a high enough volume (amplitude) -Otherwise, at a lower volume at resonant frequency...

<Moderator's note: Template removed due to replacement in a technical forum.> In the textbook, it said that standing waves only occur at the resonant frequencies of the medium. I don't understand why. My understanding of standing waves is that it is when the medium length (slinky) is a...

Hi everyone, I have recently done an experiment testing the effect of temperature on magnetism through measurement of magnetic flux at a constant distance away from the measuring device. I used a range of 0-90 C for neodymium and bar magnets, and found a reasonably linear trend, with a similar...

Homework Statement An object starts from rest and uniformly acquires a velocity of 20.0 m/s in 5.0 minutes. For the next 10. minutes the object moves with a constant speed. After 10. minutes moving at 20. m/s the object then again accelerates and reaches a speed of 15 m/s in the opposite...

Homework Statement In a configuration having axial symmetry about the z axis, a line current I flows in the −z direction along the z axis. This current is returned at the radii a and b, where there are uniform surface current densities Kza and Kzb , respectively. The current density is zero in...

Hi all, I have in mind that an engineering project tends to be quite "integrated", as in, it envolves different engineers. So, for instance, in order to build an aircraft, you need not only a mechanical engineer, but also an EE, Materials, managers, etc etc. So lots of teamwork. However, I'd...