Proportional Definition and 190 Threads

A^{2} \propto I When is it appropriate to use this formula? I don't understand how to use a proportionality. Say I have an amplitude A and I make it 2A can I use the equation to determine the intensity will increase by a factor of 4? I guess I don't know why it is a proportionality...

1. A 1000kg boat is traveling across a lake when its engine is shut off. The magnitude of the frictional force between the water and the boat is proportional to the boat's speed (proportionality constant is 70) . Find the time it takes the boat to slow to one half its speed when the engine was...

Hi Homework Statement In the ADM formalsim, we need at some point to see the normal vector (to the 3D surfaces) as a 1-form. Homework Equations How can we (simply) see that? (Please no Frobenius theorem, otherwise, with more explanation about this theorem) The Attempt at a Solution No idea!

Working the rectangular barrier penetration problem (am working through chapter 11 of the Dover QT book by Bohm) one finds that the current past the barrier is proportional to the current where the proportionality is velocity like: J = \frac{ p \rho }{m} where, the p/m factor has dimensions...

We know the speed of a wave on a string of mass density rho and under tension T goes as c^2 = T/rho. Let us play with this fact. Let there be an imaginary string of mass M between two points a distance D apart whose separation we may want to vary. Let us assume that the imaginary string is...

Homework Statement Which one of the following statements about heat flow is FALSE? (A) Thermal conduction is due to energy exchange during collisions of atoms or molecules. (B) Thermal convection occurs only in fluids. (C) The rate of heat flow due to thermal radiation is proportional to the...

Is there a difference, when looking at the stress-strain diagram, between the "Proportional Limit stress" and the "Yield Stress" ? Thanks!

There are two equations I know of that link velocity and wavelength: 1 velocity = frequency x wavelength 2 de broglie wavelength= Planck's constant/ (mass x velocity) I read that 'When particles are accelerated to high velocities, they have low wavelengths'. This means that...

VERY SIMPLE! Please help! - Energy of a gamma ray photon... Homework Statement The frequency of gamma radiation is 10^{22} Hz. What is the energy of each gamma ray photon? Planck's constant, h, is equal to 6.6 x 10^{-34} J*s. Homework Equations Energy = hf The Attempt at a...

if y\propto x at z constant and y\propto z at x constant then y\propto xz why not y^2\propto xz thank you

I have a mechanics question. "A wheel starts from rest and rotates with constant angular acceleration about a fixed axis. 1) Prove that the power at any given time is proportional to the square of the net torque about the axis. 2) Prove that the power at any given angular displacement...

Hello all, I have a question, that regards a problem I was assigned. The problem is: Why is kinetic energy NOT proportional to degrees F/C? -I understand it has something to do with absolute zero Kelivn...not C. Thanks Any help would be greatly appreciated...I need a response by tomorrow...

A red box and a blue box sit on a horizontal, frictionless surface. When horizontal force F is applied to the red box, it accelerates 4.88 m/s2. a) If F is applied to the blue box, it accelerates at 1.32 m/s2. What is the ratio of the masses of the boxes (mass of the red box/mass of the blue...

[SOLVED] ODE problem Homework Statement A situation in which the air resistance is proportional to the velocity of an object squared. Object dropped off of a building with height 100m. F = -mg + Fr Fr=.5*cw*p*A*v^2 cw=.5 p = air density = 1? Homework Equations I need to...

Could someone please explain why kinetic energy is proportional to velocity squared and not just velocity. A propulsion system that provides a constant force would typically use energy at a constant rate in order to accelerate at a constant rate and thus rate of change of velocity would be...

Do you think Presidential elections should be decided by popular vote, a proportionals distribution of electoral votes (similar to Nebraska and Maine), or by a winner take all electoral vote system? After you answer, check out this article. It might change your mind: California Proposal...

I say inertia is directly proportional to mass Frank says inertia is directly proportional to charge Of course we alll know I am right, but I would like to prove Frank wrong anyways. Instead of going to wikipedia and laughing in his face, (as is standard procedure) I would like to conduct an...

Homework Statement Show that the potential energy of a simple pendulum is proportional to the square of the angular displacement in the small amplitude limit. Homework Equations U=mgh sin^2wt + cos^2wt=1 The Attempt at a Solution I can't figure out where to start.

when theory of relativity declares speed of light to be the limit for speeds of all matter and energy and information. then, how can einstein in his mass-energy eqn talk about c squared. we can't talk about any velocity more than c. it is possible that e = mck where the value of constant k...

If I show something that a cross section is proportional to: 1 / (16p^2 sin^4( x) + 8mpsin^2 (x) + m^2) does it imply that the cross section is proportional to 1 / sin^4 (x) as well?

Correct use of "is proportional to" symbol (alpha) Hello, I am facing a problem that can be solved quite easily using the proportional symbol ( I think ), so I would like to try to use it! Only problem is.. I don't know exactly how to use it correctly... The question is :An astronaut weighs...

Hi, I'm stuck on this problem. This was fine, it's the next bit I don't get. From (1) I'm thinking I'll integrate up to get v, then again to get z, as v=dz/dt. The other alternative would be to treat is as a second order DE for z, but I tried that and didn't get anywhere. I also tried an...

Sorry guys, I thought it would be easy, but it is not. I have a random quadrilateral A,B,C,D, drawn and a random point M inside of it. Now, I want to draw a line passing through the point M and crossing the sides AB and DC at points P and Q. So far so good, but I want more, in addition...

I am given the length, elongated length, original diameter and reduced diameter of a alloy bar, and the load carried. I need to calculate the mod of elasticity, poisson's ratio and the proportional limit for the material. Got the first 2, how do I calculate the proportional limit? My book it...

Consider the following situation : There are three variables A, B and C. (and i,j,k are constants ) Keeping C constant, and varying the other two, you find that A = kB ------(1) Now, Keeping B constant, and varying the other two...

I know that a linear relationship can be represented by the equation y=mx+b, but is this also a proportional relationship? Doesn't the slope (m) make it proportional? I'm confusing myself over this easy concept. :confused:

A 1000kg boat is traveling at 90km/h when its engine is shut off. The magnitude of the frictional force f between the boat and water is proportional to the speed v of the boat: f=70v where v is in meters per second and f is in Newtons. Find the time required for the boat to slow to 45 km/h...

The above scenario is when distance and mass are held constant. ~ denotes proportional to My work: P= m*a*d/t P~ a/t a~1/t^2 when m and d are held constant so P~ a^3/2 Is this right?

What is a damping. Text books say damping is proportional to velocity. Why not damping is proportional force? or why not damping proportional to some other parameter. What does damping actually do ? Is there any practical application ?

I am one of those who cannot really go into advanced calculations and leave the simple questions behind. I have to understand physics at a basic level. For that reason I am glad some members at this forum don’t hesitate to ask very fundamental questions. For years I have just taken everything...

Lorentz Transformation --- Exponential factor, why not Proportional? When using the Lorentz Transformation, the increase in mass, or the decrease in space-time is an Exponential, why can't it be Proportional? What is the logic behind that? For instance, if SR had a proportional decrease in...

Rate of decay... "The rate of decay is durectly proprtional to the number of atoms present, following an exponential law, the rate of decay decreasing with time" - but why is this the case? Thanks in advance. :smile:

directly proportional? can anyone give an example of it? thanks alot!

Why is it that a proportional controller will always result in an offset error?

1.Which Newton's law describes inertia is proportional to mass? 1st or 2nd? 2.An object is on a slope, the graph of v-t shows that there is negative acceleration, how do you explain it ?

By definition, an infinite set is a set whose subset is proportional to the set which contains it. The sequence of numbers whether it be expressed as (n+1) or not, is infinite. Then (I am veturing into grounds I know little of here...) I am guessing it is safe to say that the numbers (n+1< or...

If a line in a triangle is a median, does it cut the triangle into two congruent triangles?

How do I calculate galactic mass as a function of r? I know it is supposed to be proportional to r. I've seen, M(r)=v2r/G And also I've seen M(r)=vrc2/G Which if any is right? And what do I use for v? Thanks so much for your help!

It always amazed my how a mice is similar to a human, but all the systems are in miniature. Why doesn't a mouse grow as big as a human? What is the mechanism regulating the organ sized, a certain number of cells? A certain size? It actually turns out that somehow the physical size is known, not...

Consider an object which the net force is a resistive force proportional to the square of its speed. For example: assume that the resistive force acting on a speed skater is f=-kmv^2, where k is a constant and m is the skater's mass. The skater corsses the finish line of a straight-line race...