Force Definition and 1000 Threads

  1. E

    Electromotive force (or E cell?) during charging and discharging

    The EMF of the cell is the potential of the cathode subtract that of the anode, consistent with ##\Delta G = -nF\varepsilon##. If the cell is running as a galvanic cell/discharging, the EMF should be positive. If it is charging, the cathode (the one gaining electrons) is now negative and at...
  2. R

    Maximizing Repulsive Force with an Electromagnet

    Hi all. New to the forum and new to making electromagnets. I want to pick your brains as I know extremely little about electromagnets. So I have a 2 1/2 inch round x 1 inch thick rare Earth magnet that I’m trying to repel with force using an electro magnet. The repel would be in bursts. I know...
  3. K

    Is non-linear Tension Force possible?

    I seem to remember from my school days that Tension Force can only be linear. Is this true? In 1 (in the graphic) the tension will follow the line of the rope In 2 there is an unbendable, unbreakable, steel cable formed into an arch. a ] In 3 which direction will the Tension be? b ] In 3 if...
  4. J

    Designing Impact Force Test Rig for Material Strength Testing

    Hi all, I have just started work experience at an engineering company in the design department. I've be tasked to develop a test rig, Similar to a charpy rig. Intended to measure the impact strength of materials. The design will consist of an A-frame structure with swing arm attached to the...
  5. K

    I Horizontal Tension Force equation

    (not a homework question - I left education over 45 years ago) Hi, this just out of interest as I have been googleing this and can't find the answer I know the equation for tension force, for example a weight on a string, block on a ramp, etc. But is there something similar for a horizontal...
  6. SpaceThoughts

    Velocity calculation of an accelerated mass based on an increasing force

    A known force is doubling (egal) over a known distance, accelerating a mass. How do I calculate the final velocity of the mass at the end of the known distance , when the mass has doubled? I don't know the time. The mass is accelerated from 0 meter and from 0 velocity.
  7. jamiebean

    Understanding Tension Force: A Beginner's Guide to Physics

    I am new to physics I have no idea how the forces work and how to calculate the tension with f=ma thank you very much..
  8. jamiebean

    What is the contact force for a 20kg object with an acceleration of 2.7?

    I have watched a couple of videos regarding contact force, but I am still confused in solving this problem. which is its contact force? Fc=ma =20kg x 9.8=196N ?? then what's the acceleration a=2.7 for? im kind of self-taught right now.. my professor does not explain these simple questions...
  9. Haorong Wu

    Friction is electricmagnetic force; why friction is not conserved?

    Obviously, friction is not a result of other three kinds of force, and electricmagnetic force is conserved, then why friction is not conserved?
  10. R

    Force acting on the contact area?

    Material - SS 316
  11. coldadler

    How can I calculate the reaction forces of a torsion spring on a wall?

    Hi guys, I am working on design where I am using a torsion spring. And I need make an analysis and see the deflection of the walls. How can I calculate the forces that applied from Spring's legs to walls. Thank you all in advance.
  12. R

    Spring force after fixating with limited stiffness

    Hi folks, I have an interesting problem here from the real world, it's a design i am working on. So I have an object that is pressed by an hydraulic press with 50kN, let's call it F_before. Then I drive in a jig to fixate it. But the part that holds the jig has a limited stiffness. Hence if I...
  13. MustafaTekinay

    How much force does a moving car exert on to the road?

    I understand that the weight of the car does not change (assuming mass of the car stays the same) because of f=mg. But I am not so sure about of the aerodynamics of the car plays a role. Say, a faster car might have more air under their wheels and might exert less force on to the ground. Maybe a...
  14. brotherbobby

    Net force and moment on a wooden bar fixed at one end

    Here is the diagram to the right. (a) Clearly, owing the fact that the bar is pinned at P, the net force on the bar is zero: ##\boxed{\Sigma \vec F = 0}##. The pin P applies an equal and opposite force to the one applied. This force keeps the bar from translating to a different position in...
  15. M

    Work done by a force along the path

    If the first equation for force is not formatted please refer to the pic. I did not post my full attempt as the problematic equation leads to a complex integral. Should I be converting r vector into its univector. The two outlined equations refer to the force. I am making an error transforming...
  16. Bengineer

    Is this still an equivalent force?

    Say I want to determine if a rope/ attachment equipment is strong enough for a person falling at some height. I am unable to have a mass fall at that height so I decide to up the mass and reduce the height. Should I use kinetic energy or conservation of momentum? Because the impulsive force...
  17. K

    I Nuclear Force Behavior: Confusing Isospin Dependence

    Hello! I am confused about when the nuclear force is attractive and when not. Based on deuteron (the book I am following is Wong), we see that we can't have bound state with isospin T=1 (otherwise we would see, for example, a stable double neutron and no proton nucleus). Also, in the book I see...
  18. archaic

    B Moment of a force about a point

    In defining the moment of a force about a point as "the tendency of one or more applied forces to rotate an object about an axis [going through a point, hence also about a point]", I see it logical to infer that it is somehow related to the angle between the force and the moment arm, but why put...
  19. V

    Tension forces of two wires in comparison to the gravitational force

    The correct answer is the second one. I honestly have no idea why this is so. I understand that the right rope has less tension that the left one since it's at a shallower angle from real world experience, but I don't really know why this is so, let alone how the forces compare to gravitational...
  20. chriscarson

    Young's modulus: Stress, Strain and Force for a Steel Bar

    As all attempts to get it right but without success this is one of the problems with my workout . Where i did wrong calculations ? The questions got the answers in brackets.
  21. Leo Liu

    Is Kinetic Friction a Conservative Force?

    If a block slides down an inclined surface under the presence of the kinetic friction, does that mean the total energy lost by the block is equal to the work done by the kinetic friction? Thanks in advance.
  22. T

    How to calculate jump height from the force and a person's weight

    If you want to see the video just search dwight howard sport science
  23. H

    B Blunt force vs cutting force in penetration

    My thought is that they both stem from PRESSURE. Sharp objects have more pressure than blunt objects given the same force and therefore can penetrate softer material better. Some of my associates are suggesting that cutting by stabbing is entirely different than blunt force. But the definition...
  24. Zouatine

    Question about potential for this mechanical force problem

    Hi! hope you are doing well , I'm trying to solve this problem ( mechanical problem) about structure with load F as it showing in the next figure , i want to determine to critical force F , the stability force ( which means if my load is bigger than the critical load my system will be unstable)...
  25. S

    I What force potential should I use for star formations?

    I'm running some molecular dynamic simulations and I came across this, https://en.wikipedia.org/wiki/Star_formation#Cloud_collapse , and I was wondering if there was a specific force potential to use in this case. Supposing I have a ensemble of heated atoms moving around and I cool them down...
  26. F

    A Force to fix sigma8 or A_s for Forecasts

    Hello, in the context of Forecasts with Fisher's formalism, I make vary cosmological parameters to compute the elements of the Fisher matrix. First, I generate with CAMB code a linear power spectrum. Then, from this, I am computing ##\sigma_{8,\text{linear}}##. Secondly, Before relaunching...
  27. Like Tony Stark

    Reaction force acting at the wheels of cars when turning

    Well, I considered the two wheels as two different bodies and I wrote Newton's equations for both of them I considered the wheel closer to the centre of the circle, we have: ##\mu N_1 =mR\dot (\theta)## So we can find ##N_1## Doing the same thing, we can find ##N_2## ##\mu N_2 =m(R+d)...
  28. r-swald

    Troubleshooting Force Calculation Errors

    I attempted this a few times but keep getting the same wrong answer... Converted the values: q1 = 6.6E-6 q2 = 1.42E-6 q3 = -2.04E-6 d1 = .03m d2 = .02m Calculation for force on 1 F1 = - F12 + F13 = - (9E9*6.6E-6*1.42E-6 / .03^2) + (9E9*6.6E-6*2.04E-6 / .02^2) (I used negative for F12 to...
  29. K

    Buoyant force and a water column

    Recently I viewed the Searaser video at After watching it, I feel the numbers given in the video could be wrong but not sure. So I'd like to know how I can calculate the amount of water pushed by the Searaser device at some height in one wave shot e.g. at 100 ft, 200 ft and 300 ft above sea...
  30. jisbon

    Dealing with magnetic force into the page?

    Since the magnetic field is pointing down, I can derive that the magnetic force is into the page. With this, I can't really imagine how the particle can move in a circular motion as I cannot visualise how the centripetal force will look like when the force is into the page (instead of usual...
  31. K

    I What is being plotted in the nuclear potential formula by Samuel Wong?

    Hello! In Nuclear Physics, Second Edition, by Samuel Wong he shows a plot of the nuclear potential (see attached) but he also gives a formula (also attached) for the most general way of writing the nuclear potential. In that formula, we have the coefficients depending on r only, but the overall...
  32. Amik

    Spring force question with a mass suspended on a spring

    Fnet=0 kx-mg=0 k=mg/x=0,25*9.8/0.2=12.25 But answer is 25(And they use 0.1 instead of 0.2 Why?)
  33. SchroedingersLion

    A Langevin equation - derivative of random force?

    Greetings, I am struggling with an exercise to the Langevin equation. Suppose we are given the following differential equation for a particle's 1D time-dependent momentum ##p(t)##: $$\text{d}p = -\gamma p \text{d}t + F(r)\text{d}t + \sqrt{C\gamma}\text{d}W $$ with a constant ##C##, a...
  34. E

    How can I calculate the tension force?

    This is my attemp of solution: Since the formula to calculate the tension is T=mg I first calcualted the weight of the bridge with the ecuation W= mg m=W/g m= 18,000 N / 9.81 m/s m= 1834 kg So T=(1834)(9.81)= 17,991 N But this seems no logical to me because the Tension force is a bit less...
  35. Like Tony Stark

    Why Is the Reaction Force Inclined in One Case but Perpendicular in Another?

    Hi, I have a doubt about reaction forces... I've attached a picture that shows two similar situations. The first one shows a rod left with an angle ##\beta## while it is on a smooth surface. The second one shows a rod leaning on a smooth surface and wall. My question is: why is the reaction...
  36. ari-anne

    Finding distance from velocity, force, momentum, mass, and time

    I solved a and b fine, I just don't know where to start c a) i=Ft i=change in p and p=mv so i=90=45v so v=2m/s b) same thing just using the other mass i=90=70v so v=1.3m/s c) v=d/t so 1.3=d/1.5 but that would be d=1.95 and the answer key says d=.96m
  37. synMehdi

    Understanding Unbalance Force in Rotating Systems

    I would like to undertand more the force caused by unbalance in a rotor, assume that the bearing is represented with 2 springs like above: The geometrical center of the rotor ##O## is equivalent to it center of gravity ##C_g## and the center of the stator (bearing) ##O'## The rotor is perfectly...
  38. J

    Canonical ensemble and Force on the Walls of a box

    Hi everyone, this is my first message after presentation so please be merciful if the notation is somewhat messy. Here's my attempt at a solution: As for points 1) and 2) I used the definition of partition function $$Z = \frac{1}{h^{3N}} \int e^{-\beta \mathcal{H}} d^3p d^3q$$ and the fact that...
  39. K

    How to Calculate the Force Required to Lift an Arm

    Hi, Hope one of you might be able to help me with some calculations :) I'm trying to calculate the amount of force required to lift an arm, based on weight, distances and angles. I made a sketch to illustrate my problem. where: Lac = Length of arm Lab = Distance from "anker-point" to...
  40. Julius Ceasar

    B Exploring Time Dilation: The Puzzle of Multiple Time Existence

    This is a puzzle to me, time dilation seems to be stating two different times can exist (at least), i am asking if this is the case not demanding it is so, please help. I do not have a science background so i will be listening closely to what those that do, have to say. Momenta Similar to the...
  41. R

    Can the Normal Force Produce a Torque on an Object on an Incline?

    Hi everyone I can't understand how normal force produce torque isn't normal force acts normally on the plane so the perpendicular distance in case if it was like block will be zero, so normal force doesn't produce torque. "case of box"
  42. B

    Analyse the cutting force of this bolt cutter

    The question is to determine the force in the small opening, delivered from the 250 N on both sides of the plier. i tried multiple things but can't get the answer right. Anyone that could help me? This is my work so far:
  43. S

    Find the force so that all blocks are at rest with respect to each other

    Free body diagram one each object: Block 1: Normal force upwards, weight downwards, tension to the right, friction to the left Block 2: Normal force to the right, tension upwards, weight downwards, friction upwards Cart: Contact force with block 1 downwards, contact force with block 2 to the...
  44. P

    Equation of Motion of a Particle acted on by a retarding force

    I really can't figure out where to even start on this question
  45. tanaygupta2000

    How Do You Calculate Time Ratios in Motion with Drag Force?

    Since given F = -kdx/dt so I equated mx'' = -kx' which gave x(t) = A + B exp(-kt/m) hence v(t) = (-kB/m) exp(-kt/m) and using v(0) = u, v(t) = u exp(-kt/m) then I...
  46. P

    Damped Oscillator and Oscillatory Driving Force

    I found the steady state solution as F_0(mw_0^2 - w^2m)Coswt/(mwy)^2 + (mw_0^2 -w^2m)^2 + F_0mwySinwt/(mwy)^2 + (mw_0^2 -w^2m)^2 But I'm not sure how to sketch the amplitude and phase? Do I need any extra equations?
  47. Ranku

    I Is Dark Matter's Gravitational Force Weaker Than Visible Matter's?

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