Force Definition and 1000 Threads

Is there any astronomical indication that gravitational force between dark matter might be weaker than between visible matter?

Summary:: I try to find the resultant force on "q". I think I have to find the value of Q, but I'm not sure. I Know F1 = k|q * 2Q| / 3² and F2 = k|q * Q| / 2² Hi, this is my first post on this forum I hope I posted in the right section. I try to find the resultant force on "q". I think I...

As I have shown in the picture even if their is minimal change but shouldn't it increase after a long time as minimal changes will keep accumulating.

Source: Principles of Nano-Optics, for Lukas Novotny and Bert Hecht.The equations above represent the electric field in the second medium when a light hit a surface and the condition of TIR (total internal reflection) is satisfied. Actually this is what called Evanescent field. The point is if I...

I calculated the potential energy of the particle as follows : But I am not sure how to calculate the kinetic energy. I know that if it was a satellite orbiting a Earth, I could use ##\frac {GMm} {r^2} = \frac {mv^2} {r}## to calculate the velocity v and they I could calculate kinetic energy...

Hello; What equations on mechanics can I use or study in order to measure the maximum force in Newtons the surface of the metal Steel box can hold. Details: Watch the image below, we have a metal box made of let's say steel, this box have a shape of rectangle of a thickness of for example 1cm...

Okay let's say we have a wheel attached to a fixed axle, free to spin, ignore friction and we apply a force on the edge of the wheel. That force creates a torque, does the axle have an opposing force to keep the wheel/axle assembly from accelerating linearly? Ive learned on this forum that when...

Why does the force due to surface tension act parallel to the surface here? I know that surface tension is a result of absence of cohesive force above the surface and thus the water molecules below pulls the surface down and keeps it like a stretched membrane. If the surface is pressed as...

When I blow a balloon with CO2, it falls as it is heavier than air. Then it is gravity that causes the balloon to fall. When I buy a balloon filled with helium gas from a store, it floats as it is lighter than air. But what force is causing the balloon to float?

I want to focus this question on understanding the force ##F(r)## I get (thus, I want to focus on c) ). However, below the dashed line, I included steps on how I derived ##F(r)##. We are going to work in polar coordinates. Knowing that the acceleration is: $$a = \Big( \ddot r - r \dot...

Hi, I am trying to find out Force on a rigid body when it is completely inside a fluid with density p, i.e. the body is completely drowned in the liquid and then another liquid is pushed into the container with different density 'r' (such than r > p). Thanks.

Background: My understanding is force and mass are two different things. Mass is how much matter is in a body Force is mass multiplied by an acceleration. Here on earth, that acceleration is 32.2 Ft/s2. Therefore, for the same mass, there can be different forces depending on the...

I solved this question until the end of the "c)Find the distance until the boat completely stop" However I can not solve the integral I encounter in the solution of the last part of c). Would you please check for math and maybe my mistakes and tell me what to do? Here:

I believe I solved this. Is this solution true? Can please anyone just check?

Good afternoon, I have some doubts about the tension force suffered by a spring to which a mass is hung and which is making a simple vertical armoin movement. My doubt lies in the fact that at the bottom of the pier (where the mass hangs), the spring exerts the restoring force that is given by...

ans is opt4

I tried solving the differential equation by integrating both sides wrt t but this does not work out and I am doing something wrong. How do I integrate such an equation properly? d²x/dt² = -k²/x³ => dx/dt = -k²t/x³ => x = -k²t²/2x³ + d

I got this picture from a superconducting parametric amplifier text I was reading. (The picture is a mechanical analog of a non-degenerate parametric amplifier.) If the balls(red and blue) were oscillating at their own natural frequencies, and an external force is driven(purple), how would the...

lets say a hammer of 0.5kg strikes a nail at 10m/s. The nail penetrates into the wood by 1cm. The reason why the nail stops is because friction has eventually overcome the nails momentum. The retardation of the nail can be worked out, but Can you calculate the force that stops the nail if you...

Summary:: Calculating the inclination angle A stick is on two springs with spring constants D1=500N/m and D2=300N/m. Consider the stick is without mass and can rotate around the point E, which is distant from spring 1 with 0,1m and from spring 2 with 0,8m. A force F=100N pulls the stick up...

I'm sorry but I can't even attempt this question since I'm pretty much clueless, I got the notes but I don't understand them.

I've been working on this problem for a couple days now and I'm clearly missing something. I first went ahead and solved the triangle. Hypotenuse is 5, height is 4, the last side is 3 and the angle is 53 degrees. I went ahead and did the sum of forces in the y direction = Fn - Fbucket - Fearth =...

μThe magnetic field is supposed to be B=μ0i/(2πr). I think that the force would be aimed upwards. Now I tried to divide the wire BC to infinite smaller wires where B is roughly constant in each one of them. What I get is: However this is not correct when I plug the relevant numbers in it...

How to find potential energy if force depends on both position of particle and time ? Suppose force is : f(r,t) = (k/r^2) * exp(-alpha*t), k, alpha = positive constants, r = position of the particle from force-centre t = time Is this force a conservative or non-conservative ?

Hello all I am trying to find the hydrostatic force of a cylindrical tank of water. I was hoping someone could help point me in the right direction. I have a cylindrical water tank. The dimensions are as follows:- I need to find the magnitude of the hydro static force per unit of...

In Einstein's theory, gravity is caused by the warping of spacetime. This leads some people to object to gravity being referred to as a force. However, to me it is correct to say that a paperweight resting on a desk is exerting a force on the desk (and vice versa). Is this a correct statement...

hi, I have read that the process of repulsion between two similar charges, such as two electrons, is mediated by the exchange of a photon. This photon somehow merges with the nearby electron and somehow directs the electron to move in the opposite direction. Is this correct? I don't quite...

The figure is in the attached image. My attempt: I(wheel-disk system) = 0.5mr^2 + MR ^2 = 0.5(0.2kg)(0.1m)^2 + (1.5kg)(0.3m)^2 = 0.136(kg)(m^2) Fnet(of object) = Ma Mg - T = Ma T = Mg - Ma Fnet (wheel-disk system) = (M+m)a Mg- Ma - Fr = (M+m)a a = 0 because system in equilibrium Mg -...

Hi Guys, I am trying to keep this as simple as possible as I only need a ballpark figure. I am sure there are thousands of other variables which need/could be taken into account, but for this purpose, as simple as could be. A door in my house slams when other doors/windows open. The door is...

Hi, I have a simple question but I want to be 100% sure that my reasoning is correct. Take a look at this picture showing forces acting on an airfoil: Green forces (X and Y components) are known from CFD software but I need the values of blue components (lift and drag). Of course for zero...

Hello all I was hoping some could help shed light on the idea of a Point Of Action of a force. I have a rectangular wall of 32m which is holding back water, the water is at a height of 29m. Where is the point of action of the force? The problem is illustrated below:- I have been told that...

When is weak interaction actually a force, rather than merely cause of some process? Not in beta decay - it is process. There are simpler weak interaction processes around: elastic scatterings that change only momentum but not taste. But those are still processes and are over as the particles...

Hello, Just refining my understanding of the work-KE theorem and seeking some validation: The work-kinetic energy theorem states that the mechanical work done by a force (be it conservative or nonconservative) is always equal to the change in kinetic energy of the body. The net force in a...

Hi All We know that beta decay is and ejection of an electron from nucleus, making a proton turn into a neutron (and a neutrino). Is it correct to say that is the weak force responsible for the increasing in the distance between electron and proton during this process (since the feel atracked...

I need to conduct an experiment and measure how what is the coefficient and force of friction of the rubber that pushes down along the edge inside the syringe. The thing is I can’t use a dynamometer.

Homework Statement: An open tank with a rectangular side 1 m wide and 4 m high is filled with a liquid of variable specific weight, γ, with γ = 50 + 2y (N/m3), where y is measured vertically downward from the free surface. Find the magnitude of the force on the side of the tank. Homework...

Hi all I am trying to get my head around some units of force. 1) I have units of:- Kg * m / s^2 Am I correct in thinking that these are units of Newtons. So if I had 560Kg * m / s^2, then can I say 560 Newtons - would this be correct? 2) Secondly I have units of:- kg/s^2 I have no idea...

Hello all I am trying to understand the pressure equation. I have the following question:- I understand this, to me what this says to me is the total force acting on the wall as a result of the water of 12m is 706320 Pascals.This is where I get a little confused, I have the following...

If there was an atractive force between air molecules, how could this be measured? The force should be small. In the range of the force between watermolecules (hydrogen bond).

I first wrote down that 55% = Eout/Ein I also know that W = (Facos20)(4) and I substitute it into the first equation 55% = Eout/[(Facos20)(4)] But I'm missing two variables here. Did i forget something or is the question missing some information?

Hi all! I have used this forum a few times and it has been very helpful, however now I am stuck. I have completed the question above however I have conflicting information regarding the Tensile and Shear force being applied to the rivet. I use the following calculation for this: Shear Force...

Hello, I am reviewing the concept of tension, a force that expresses the internal tensional state in a body (rope, chain, string, solid body). My understanding is that the force of tension "derives" from the stress tensor and relates (it is the product) the diagonal tensor components to an...

Posted on more pseudescience related sites is a story about, a group that claim to have discovered evidence of a new force of nature, with a claimed sigma of 7,7. The arxiv paper have not yet been peer-reviewed, so I am not sure if it is allowed. If not I am sorry, and will understand. I am...

I know muslces have fibers and all sorts of structures but how do they actually attract themselves to each other on a very atomic level? Is it some sort fo chemical bonding force or?

A container of height 3m and width 5m is filled with water upto 2 m. It is accelerated such that the water is at the brim (it is about to spill). When it moves with this acceleration find the force acting per unit width on the vertical wall. I found the acceleration for the condition provided...

Hello, How can I calculate the force that must be exerted on a ball inside a rubber tube? Thanks

I'm not so sure how to begin with this problem. I was thinking of usign superposition. I think that the field on the conductor due to the parallel segments of the coil is zero, since Ampere's Law tells us that the field outside the solenoid is zero, right? For the perpendicular segments, I used...