Forces Definition and 1000 Threads

Are forces subject to the Lorentz transformation? Not force carriers; I already got that question answered, thanks to @PeterDonis. But forces. The different forms of them, such as the contact forces etc.: https://en.wikipedia.org/wiki/Contact_force With time dilation, does the rate of force...

Are there any limits to how fast forces can exert influence... or are they all instantaneous? How fast are the forces of a collision? I think frame dragging, with gravity, shows that at least gravity is not instantaneous, because if it is instantaneous, then how would it produce drag - it...

I've inserted a photo of the figure, hope everyone can see it. SOLUTION: 1. I first solved for the angle of 100 N and 50 N since I need the force that is perpendicular to point A. >> Angle of 100 N theta = arctan(3/4) theta = 36.870 degree >> Angle of 50 N...

Hello PhysicsForums! Here is my attempt at a solution for the problem stated above: Where m1 and m2 are the masses Where Ff1 and Ff2 are friction for each mass Where a1 and a2 is the resulting acceleration Where S is the fore of the wire (threadforce) Where FN is the normal force The answear...

Forces on rotating disk object Hi. Is it convenient to ask following question. Suppose we have solid circular object and 5 different moments like in the picture:In moment 1 we apply force (downwars direction) so as to start rotating the object around center of the mass (green dot) , Only...

If the dipole is to be in equilibrium at all positions as it's moved so that it's always inclined at 60° to the horizontal, then the torque due to electric field needs to be balanced by torque due to external forces ##F_{ext}## as shown in above diagrams. But such external forces will not make...

TL;DR Summary: Please Help. I need an answer for an Investigation if a uniform bar of length 2200mm is supported evenly on 2 points (1 and 2) 1190mm apart. The bar is comprised of 3 sections (A, B and C) of varying masses. Section A and C have equal mass and volume and is comprised of the...

I am currently designing an alternative to normal acoustic drum lugs and I need to find the forces that are felt by the tuning rods of a drum for the engineering background to my design. I have been able to use the 2D wave equation assuming uniform tension on the membrane and found values of the...

Also, I wonder if a system can have work done to it due to its internal forces, as it is generally said that the work done due to internal forces is zero or at least I have learnt that(cannot trust my knowledge anymore, lol). I got this question in my mind because of a situation in another...

Hey everyone. Let's say you have a tall tree. say, 10 m tall. Take a cubic cell 1mm in dimensions. Suppose the cell is at 1 m high in the center of the trunk of the tree. What are the forces acting on the cell? let's say tree cell's mass is t grams. its weight is F= ma = t (9.8) = 9.8 t...

This is how I interpreted the problem, a) The net torque about point A is zero. This is because the forces F1 and F2 are equal and opposite, and they act at the same distance from point A. Therefore, they produce torques that cancel each other out.. The force F3 doesn’t does not produce any...

Hello! In the following image, is it true that S1 = mg/2. Thanks for answears!

TL;DR Summary: Solar sytem forces on Unity Hello ! For my last year in my school, I've got a project to do, and I wanted to recreate the Solar system with forces on Unity. My forces are Velocity and Acceleration (I'm using the Frenet's formulas). I'm sorry I'm not a physicist and that's why...

The premise is that whenever you watch Battlebots or Robot Wars, there's usually a robot on there which has a vertical drum spinner which weighs half the robots weight and spins at thousands of RPM, and whenever the robot turns, it cocks one wheel in the air due to the gyroscopic forces at play...

Picture of problem: For the object to be moving, it must overcome friction. ##f=0.5*0.6F = 0.3F## ##mg=22N## Upward motion: ##0.8F>mg+f \rightarrow 0.5F>22 \rightarrow F>44N ## Downward motion: ##0.8F+f<mg \rightarrow 1.1F<22 \rightarrow F<20N ## I think correct option is D. Can you please...

neglect friction and motion (sliding) and G(sphere)=20N. In this question I reached two different result with two different solving method.But one of them is false according to answer key. My question is why first solving way is false? Because the first solution way makes sense to me. If we...

This might sound as a dumb and silly question but if you think about it, it makes sense. If we wrongly assume that gravity is a force just like any other, and given the fact that time is closely related to gravity and that gravitational time dilation is a thing, wouldn't reverse time travel...

The screw eye is subjected to two forces, F1 and F2. Determine the magnitude and direction of the resultant force.

Hello I have alwayes seen FEM applications for static structures while each " finite element" of a bar linkage mechanisms should be subjected also to a variable inertial force besides its constant weight how do FEM softwares compute inertial forces ?

I think if we don't consider electron's/proton's mass then we can say that the amount of charge doesn't need to be equal according to Newton's 3rd Law. I mean having q on one ball and 2q on another ball , still makes the angles having the same size. Is it true ? What if we consider proton's...

1.52cos(31)+Fbsin(Θb) = (0.305)(9.8) Fbsin(Θb) = 1.69 Now for horizontal direction: Fbcos(Θb) = FLsin(ΘL) cos(Θb) = FLsin(ΘL)/Fb cos(Θb) = (1.52 x sin31)/1.69 cosΘb=0.464 Θb = 62.35 I thought to find Fb I would just plug the Θb value into one of the trig functions, but apparently both of my...

I was confused by how to work this problem in a rotating frame. The solution read that the centrifugal force on the mass should be of magnitude 𝑚𝑤𝑅^2. However, I thought it would be 𝑚𝑤𝐿^2 where L is the distance between the mass and the center of the circle (L = l + R). What am I missing here?

I don't know much about forces, speed, and what is needed to cushion a blow. But after seeing the serious injury of Damar Hamlin, is there a way to create equipment that can easily cushion any impact an NFL player can apply to another player? Or does the equipment get too heavy by that point...

Hi all, I am new to the forum and hoping for some help please. I work in the rail industry and we use chock blocks to stop trains or carriages rolling. I would like to know about the technical side of how and why the chock stops the wheel from moving. Obviously it wedges the wheel to stop...

Hello, id appreciate your help for the following case: in a room, a zero weight rod has zero friction bearings at its extremities. One of his ends lies on the floor, the other is against a wall, forming with it an angle alpha. A verical force fv is applied to the 'wall end'. How to calculate the...

The answer is .32m. I set the elastic potential energy as equal to the work, but at first I put the force in the work equation as (F elastic - F kinetic friction) times distance and rearranged. 1/2kx^2 = (kx-Ff) d (0.5) (22) (0.035)^2 = (22 x 0.035-0.042) d 0.013475= 0.728 d 0.013475/0.728 = d...

Hello Everyone, This is not a completely new dilemma but I have been discussing it with several people and teachers and read different physics textbooks and continue to get different perspectives, sometimes overlapping sometimes not. Let me explain and summarize: Forces are interactions...

This was how the solution was arrived in the text, Net torque = F block x d block x sin ϴ0 + F rod x d rod x sin ϴ0 - T R sin 90 0 = 2mg x 2R x sin ϴ0 + m x R x sinϴ0 - T R T = 5 mg sinϴ0 I'm wondering do we have to resolve the forces for rod and block in to...

Suppose n book stack on each other. Since each book have the same weigh then the last book exert a force N=nmg on the surface so it has the biggest static friction. But if we treat the whole tower of books as one particle it also has N=nmg. This mean if we exert enough force in the last book...

Hello, Forces can be concentrated (when acting at a single point) or distributed (when acting over a surface or line). In the case of distributed forces, we can find the resultant concentrated force by calculating a surface or line integral of the force density ##f(x)## w.r.t. an area or length...

If I am not wrong, F = 2*10*9.81*4/0.2 = 3924N (0.2m considering 5% stretch in 4m long rope)

Suppose I'm considering a system of N particles that are constrained in their possible motions and so there are less that 3N generalized coordinates. Suppose now I perform a virtual displacement on one particle, which due to some constraints might force some other particles to more virtually...

Since gravity is caused by mass deforming spacetime, is gravity actually a force or just a consequence? Are there really 4 forces in nature or just 3?

I understand, and have unwillingly come to terms with the fact that virtual particles can carry negative momentum. This explains how momentum can be conserved in attractive forces via particle exchange. I have a problem with this that I cannot reconcile...wouldn't this imply that as a particle...

In this 2D figure below, I can place: a motor at O a motor at J gravity on each link I can use Hamilton's principle, modified to the principle of virtual work and I can compute the motion of the linkage system. I do not have to account for these force FOUR forces (in this planar problem)...

The answer is (B) but I don't understand why (C) is wrong. The force acting on the hinge has two components, horizontal and vertical. The horizontal component must be to the right to balance the horizontal component of tension but the vertical component can be either upwards or downwards. Wow to...

We define Electric Field Intensity vector at a point as the force experienced by a unit positive charge kept at a point. Is it correct to define B vector similarly that is, is B vector the magnetic force acting on an unit magnetic north pole and is it correct to call B vector Magnetic Field...

In a car we turn the wheels to steer. The wheels however are spinning about their axis of rotation when the car is in motion. Does the revolving motion of the wheels cause a force that opposes trying to rotate the wheels around the other axis to steer? How much opposition is created? Here's...

In the solution given in the above image, I am unable to understand and prove why N1=f and N2=W. I have tried balancing the torque on different point but still unable to prove. Explain how N1=f and N2=W can be proved. The justification for N1=f and N2=W which I have so far read is that it is...

Is there an experiment that shows strong force grows with distance?

Hello, I' m trying to make a linear static analysis (Finite Element Analysis) on the following hand tool. I want to determine the boundary conditions. In order to do that I have decided to use a force couple to represent the forces that a bolt exerts on the jaws of this spanner. Despite using...

I wonder if forces of attraction really exist. Can two things separated by vacuum get attracted? It seems impossible.

Hello, The classic problem of a block dropped on a vertical spring from a height ##h## above the scale: find the overall compression distance of a spring when a block is dropped on it and brought to rest. This problem is easy to solve using conservation of energy, potential gravitational...

So.. question: - How do I know that only the pin is at work at E and not those 2 beams? my guess: It is because those 2 beams are connected to the pin whilst the pin is the one that exerts a force on that walking beam DEF?

If we take two positive charges +q1 and +q2, and we hold q1 still, does q2 experience a repulsive force due to q1 repelling q2 AND a repulsive force due to q2 repelling q1? That is ##|F| = 2*\frac{k*q1*q2}{r^2}##

My textbook is deriving wave speed on a string under tension with confusing thetas. It assumes ##\tan \theta_1 = \frac{-F_1}{F_T}## and ##\tan \theta_2 = \frac{F_2}{F_T}## which confuses me. I know for sure theta is the angle due to the position of y and x, ##\tan \theta = \frac{y}{x}##, but I...

Greetings, I have tried to find the reactions of the bearings on the Y direction in the intermediate shaft. but I couldn´t find the numerical results of the solutions here is my attempt: in order to find the forces I did the moment equilibruim around the point A and B With FT1 FT2 and...

A very simple (I thought!) question: I'm just looking at the first part, finding the reaction at the hinge A. Here is my annotated diagram, with the reaction and A resolved into it's X and Y components, the force at E labelled as Fe and the length of ED labelled as L. Considering the body...

Suppose the car is moving to the right, so if the wheels roll without slipping, they are rolling clockwise. To get the wheel to slip, a counterclockwise torque would need to be applied to cause the wheel to have some angular acceleration. If the wheel was slipping, then the bottom of the wheel...