Forces Definition and 1000 Threads

Suppose one has a box moving through flat space-time with a stress energy tensor ##T^{ab}## that's non-zero inside the box and zero outside the box. How does one compute the normal forces on the faces of the box associated with it's motion? I am assuming that the normal forces are measured...

Imagine such situation: A bus is moving at constant speed, a man is standing on the bus and is not holding to anything - he is simply standing. Now, the bus starts breaking with constant negative acceleration and so the man will change his relative position due to the force of inertia. Now...

This may be an overly-broad question, but is there any reason to think we will ever have the technical mastery over gravity, the strong force, and the weak force, that we have over electromagnetism? Example: turn on a switch, gravity; turn off a switch, no gravity.

Homework Statement There is a system of 4 points located along a circle of radius R. Points are connected by undeformable ropes (pink on the picture). There is a force applied to each point. Scheme: https://we.tl/MsCEViCQdB I need to find resulting force in the system. The Attempt at a...

I am getting correct equations on using the Lagrangian method in Systems with no non conservative forces, but when I use it in Systems with friction, sometimes I get correct equations, and sometimes I do not. Most of the equations have some problem with the coefficients of the frictional forces...

Homework Statement Consider beam “A-B” and strut “C-D” from Figure QA1. The beam “A-B” is hinged at point “A” and hinged with strut “C-D” at point “C”. It has an applied force of 8 kN applied at point B as shown in Figure QA1. Strut “C-D” is hinged at point “D” and it is also hinged with beam...

Homework Statement Figure shows two blocks in contact sliding down an inclined surface of inclination 30.The friction coeffecient between the block of mass 2kg and the incline is μ=0.20 and that between block of mass 4kg and the incline is μ=0.30.Find the acceleration of 4 kg block (g=10m/s2)...

i have a assignment for my MATLAB (first year) class, and I am slightly confused om what exactly i should be coding. im not struggling with the coding part, but what i am suppose to code. im used to coding based on what it is needed. So, for my project, I am suppose to represent the forces...

Is the adhesive force greater in a smaller tube then a bigger tube at the top? So would it take more energy to take out water at the top of the straw from the thinner straw? Or would, due to gravity cancelling eventually the capillary rising, the adhesive force at the very top of the straw is...

1. Homework Statement In picture Homework Equations f=ma The Attempt at a Solution i can use Newtons equations here, but i am confused about the frictional force.. so it doesn't specify whether it is a frictional or unfrictional surface.. is there something I'm missing here? does friction not...

1. Homework Statement in picture Homework Equations My equations are netforceyA = -MG + Friction between A and Hand + Friction between A and B netforceyB = -MG + Friction between B and A The Attempt at a Solution Friction between A and B are equivelant due to Newtons third law since they...

I had an argument with my friend regarding constant forces.He said that work done by constant forces are conservative as we can take the force out of the integral and it doesn't depend on the path .But the fact that this information is not given in my textbook as well as by teachers makes me...

Homework Statement Homework Equations f=ma The Attempt at a Solution ( i have put numerous different forces into the answer box and nothing worked. i was just taking a screenshot of problem here) Edit: never mind about kinetic friction with wall i just saw that there is no friction with...

Homework Statement Two blocks each having masses of 3.3 kg are connected by a wire CD and the system is suspended from the ceiling by another wire AB.The linear mass density of the wire AB is 10X10^-3kgm^-1 and that of CD is 8X10^-3.The speeds of the transverse waves produced in AB and CD are...

Homework Statement Two forces ##F_1## and ##F_2## are applied on a spool of mass ##M##, moment of inertia, ##I##, and radius ##R## as shown in the figure. If the spool is rolling on the surface, find the ratio of forces, ##F_1/F_2## such that friction between spool and the surface is zero...

If I am towing a 10,000 lb. trailer downhill on a 6% grade at 65 mph and I hit the brakes coming to a complete stop in about 5 seconds, how much force is being applied to the trailer hitch? I am trying to build my own hitch and the forces applied will help me determine plate thickness. I will...

A 100 pound force and a 150 pound force act on an object. If the angle between the force 40 degress, find the magnitude of the resultant force and the angle the resultant force makes with the 150 pound force.

Hi , The Static Friction force of an object on a ramp(inclined plane) making an angle with the horizontal is greater than the weight component down the ramp. My textbook says that this means that the object on the ramp is stationary as the frictional force is greater than the weight component...

Homework Statement A 5.0kg block of wood sits on a table with a string running over a pulley suspending a mass. The largest mass that can be suspended without moving the block of wood is 0.75kg. a) Calculate the coefficient of friction in this case. b) What type of coefficient of friction has...

Homework Statement I've been trying to find the unknown forces for this beam so I can complete an FEA analysis. Homework Equations ∑mz=0, ∑fx=0,∑fy=0 The Attempt at a Solution Attempt is attached

Questions 1.) Here, the negative charge from the wool is transferred to the plastic rod. I'm curious as to what determines which object is responsible of transferring their charge to the other object. Like why didn't the plastic rod give its negative charge instead? 2.) If we rub 19 more...

Homework Statement This is more of a question of applying the correct principles to a range of problems involving a horizontal rod hinged to a wall that is then supported by another rod. The support rod is also attached to the wall from above or below and then attached to the horizontal rod, so...

Homework Statement The problem asks to find the reaction forces for each of the bearings. For such bearings, the reaction forces can be looked up in a textbook, but they just act perpendicular to the shaft. Homework Equations Sum of the forces and moments = 0. The Attempt at a Solution I...

Hi! I know little about physics, but I am very well educated , with an inquisitive mind. First the context, then my specific question A. Context The practice of windsurfing has brought me to try and understand the principles of hydrodynamics, in order to make my sailing more efficient. As...

Homework Statement Nikhil is probably eating his daily snack at this time. Old Man Miller comes back from the store and takes the 0.150kg sandwich from Nikhil as he begins to run away. Nikhil is running at 7.5m/s away from me when I hit him in the head with the sandwich that was moving at...

Homework Statement Two crates, A and B, are in an elevator as shown. The mass of crate A is greater than the mass of crate B. a. The elevator moves downward at constant speed. ... iii. Rank the forces on the crate according to magnitude, from largest to smallest. Explain your reasoning...

Homework Statement Mariana is volleying with Old Man Miller and returns one of his feeble tennis serves. He serves the ball such that it is moving at a speed of 35km/h [Forward] when she strikes the 0.060kg ball and sends it back over the net at a velocity of 55km/h[Backward]. a) If the ball...

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...

Homework Statement A light elastic string of natural length 0.3m has one end fixed to a point on a ceiling. To the other end of the string is attached a particle of mass M. When the particle is hanging in equilibrium, the length of the string is 0.4m. (a) Determine, in terms of M and g (take g...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails, weigh 10 kg and 20 kg, respectively, and are both the same size. c) If...

given: 128kg F1 = 28 N, F2 = 57 N, F3 = 38 N, θ1 = 30°, and θ3 = 60°.They are asking for the angle (measured relative to the positive direction of the x axis in the range of (-180°, 180°]) of the asteroid's acceleration? The problem is displayed on quadrant I and IV for vector notation I got...

The question is: Are acceleration independent forces that obey the Helmholtz condition necessary of the Lorentz form? ============================================================================== According to the "On Feynman’s proof of the Maxwell equations" (Hughes, R. J. (1992) American...

A frictionless incline (the triangle below) is bolted to the floor so that it can not move. A block of mass m slides down the slope, which makes an angle with the horizontal.a)Draw a free-body diagram for the block, labeling all forces uniquely. b)Describe all the forces listed above in the...

Homework Statement Hello, it is me again, I recently posted about a question on moments and centre of gravity with two planks both 10 Kg in mass and 2m in lengths, uniform, situated on top of each other as shown in the picture. The question asked for the maximum length of x that the system...

Homework Statement So I've spent many hours on here and deep deeeeeep in my textbooks trying to learn things...that pertain to the Egg drop experiment I am almost done with everything I need but I was wondering. I've read that it takes approximately 25 Newtons of force to break an...

I want to build a bass guitar stand for my guitar using wood, I'm modelling it after the image shown. The alterations I'm making are to increase the height of the legs , to place an attachable weight below the stand . This will allow the stand to have a lower center of mass and will greatly...

Homework Statement From a physics multiple choice test: "A car is raised to a height of 10 meters. The car is at rest both before and after it has been lifted. The mass of the car is 900 kg. The total work that has been done on the car during the move is" (The right answer is: zero). Wnet...

Homework Statement A wheel is spun up from rest by application of a force applied to the rim of the wheel. Consider the wheel to be in the plane of the paper, rotating clockwise. This force must point in what direction. 1) at the bottom of the wheel, pointing right 2)at the top, pointing left...

Homework Statement I don't remember exactly what the question was because it was on a quiz today. It said something along the lines of "a ladybug is on a turntable and begins to slip at .5 m/s. Find the coefficient of friction. Homework Equations Fc = (mv^2)/r a = v^2/r Ff = uFn I think...

Homework Statement Homework EquationsThe Attempt at a Solution what's the Fa and Fb? my logic is Fa = Wa - N = mg - ##\frac{N}{\cos \theta}## so is Fb... so the ratio is 1. But I know it's wrong. What will make the difference between Fa and Fb? can anyone give a clue please?

Homework Statement Homework Equations ##\tau = rFsin(\theta)## ##\tau_{net} = I\alpha## ##F = -kx## ##kx = mg## The Attempt at a Solution I don't understand how the restoring force from the bending of the ruler behaves (so I have no idea how to apply torque here). I also don't understand how...

How does one correct for tidal forces when (classically) simulating the orbits of solar system bodies?

Hi. I've read the following argument why the torques generated by internal forces add up to zero: Since by Newton's third law all forces come in pairs, so do all internal torques, adding them we get...

Homework Statement An elevator that contains three passengers with masses of 72 kg, 84 kg, and 35 kg respectively has a combined mass of 1030 kg. The cable attached to the elevator exerts an upward force of 1.20 x 104 N, but friction opposing the motion of the elevator is 1.40 x 103 N. ·...

Hello. Lets say I am riding a unicycle rolling along the wheels direction with some velocity v0. I know that for the unicycle to turn a curve the centripedal force must be provided by the static friction with the rode that acts against any slipping of the wheel. I am however having trouble...

Suppose we have a rotating frictionless disk and there is a rotating observer on the center of it. Furthermore, suppose a very small ball on the disk's edge. Now we clearly know that the ball is not moving but the rotating observer sees the ball following a circular path with an angular velocity...

Homework Statement The pictue shows a symmetrical framework. I should calculate the bar forces. and make a "Clear Cut".I*m not shure because of the left movable bearing (on the left side)!? Homework Equations total x=0 total y=0 total M=0 The Attempt at a Solution Here is my "Clear...

For each action there is an equal and opposite reaction (third principle), and no one would ever think to say that the action is "real" and the reaction is "apparent". Also the centripetal force is an "action" to which (as it happens for all the actions) it corresponds *always* an equal and...

HI, I've attached a rough diagram(emphasis on rough) of a waiter holding a tray, there is a downward force of 5N acting on the clockwise side, and a downwards force of 25N on the anticlockwise side of the pivot, which is his middle finger. The total force acting down is 30N, so therefore the...

Hi all, this is my first post. It seems around eight years ago I was on a similar brain-wave-length as Laurence Kemball-Cook, with his idea to create a power generating flooring surface... only he had the know-how to bring the idea to market, so credit where credit is due. (though now I wonder...