Force Definition and 1000 Threads

  1. inuka00123

    B How hydraulic pressure can change the magnitude of a force?

    how liquid based systems e.g. hydraulic systems, can change the force which applied on it is smaller pistons, and transfer much force to a larger piston in area, my textbooks says 1:10 ratio hydraulic system can deliver ten times the force applied on the smaller piston to the large piston. it...
  2. R

    Force to move a 24 tonne truck one foot in one second

    The acceleration in one second over one foot distance is 0.6096 m/s2. So, F=m⋅a=24,000×0.6096=14,630.4N Therefore, the force required to move a 24-tonne truck one foot in one second (from rest): Force = 14,630.4 N ≈ 3,289.5 lbf ≈ 1.492 tonnes-force Is that correct?
  3. Arend

    B Why is gravity a weak force at the atomic scale?

    Hi. Following the classical mech. g=-GM/R^2, for quantum distances the gravity force would be strong. What are the quantum mechanisms that cause the effects of gravity to vanish? The position uncertainty or the probabilistic wave function can be a justification for suppressing strong...
  4. M

    I Direction of magnetic force

    I am reading chapter 8th of Griffiths' electrodynamics (4th edition) on page 361 I stumbled upon this: For figure 8.3 I don't understand why does the magnetic force of charge q1 points upward? According to right hand rule the thumb should point in the direction of v1 and then fingers curling...
  5. syllll_213

    Force needed to raise a backpack

  6. syllll_213

    Force of car pushing on a truck

    HI, when I looked at this question, I thought that due to the acceleration, we should conclude that there is an overall force acting on that direction, and therefore the two bodies will accelerate. And since the car is the only with functional battery, it should exert greater force? Am I wrong...
  7. M

    Can we increase force of an open nozzle that runs on compressed air ??

    How did you find PF?: Online browsing Hi, i am an operation engineer. We are having a bottleneck where a nozzle ( air knife/ long strip with multiple orifice), used for removing stagnant water is not generating enough force and some water still stagnates. Maintainance engineer have increased...
  8. M

    Spring force required to overcome friction between two blocks

    200 x amplitude= 0.4 x 1.8 x 9.81 But the answer includes the big mass as well. Why ? Isn't it frictionless ? Doesn't friction depend on the weight of the small block ?
  9. C

    help whit problem of college admission exam

    Σf=m*a Fe-w=m*-a is this correct?
  10. K

    Force pulling on a string at an angle with a block at the other end

    I can't understand what is going on here. My intuition tells me that the traction pulling on the block should be equal to F. Apparently, however, the problem would have me believe that this is not the case, as it gives me a 30° angle at which the force acts and a 6-8-10 triangle as ways to...
  11. S

    B direction and magnitude of force on an arrow that left a bow.

    sir, I would like to know what the angle formed between the direction of impact and the length of arrow that leaves a bow? If it exists can it be reduced? thank you
  12. N

    I Coulomb's law taken to the extreme

    So Coulomb's law is this simple formula for calculating the force between two charges. Kq1*q2/(r^2) (Disclaimer: I know this computation is not actually possible I was just wondering if it would give the correct result) I was wondering if it is valid to sum the force vector from every charge...
  13. WhiteyM

    Velocity of a water jet exiting a water tank drain tube

    I originally thought about working out the force F with which it pushes the water thru the tube using pressure, and after using impulse and momentum to get the initial velocity, but sadly it wasn't successful. If anyone can help, please.
  14. S

    Frequency of pendulum in the presence of electric field

    I imagine the setup to be like this: the pendulum is moving horizontally, then it will experience electric force upwards so there is additional upwards acceleration, in addition to the acceleration from restoring force. Since the resultant of the two accelerations is not directed horizontally...
  15. Y

    Which of these rods are in equilibrium?

    (My attempt of drawing the forces is the figure with the arrows). Intuitively I would say that non of the rods are supported in any of these configurations, but I struggle to give a good explanation for why. I could guess that B would be able to keep up, however summing the forces, it seems just...
  16. kozmosnak

    Question about Momentum and torque

    TL;DR Summary: I have this Question, and I have no idea, how am I supposed to set the Forces to create a balance since they are not perpendicular to the moving arm. I have this question I have spend a lot of time on. It basically shows two sticks which are connected in the middle to create a...
  17. S-Ragnork1729

    Upside Down Paper-Glass Water Experiment

    $$F_{down} \leq F_{up} $$ $$\Longrightarrow mg \leq \rho g(h-H)\pi r^2 $$ $$\Longrightarrow m \leq \rho (h-H)\pi r^2 $$
  18. yargd

    B Hold a hammer at the top vs bottom of the handle

    Hi all, When we hold the hammer at the top of the handle, we can swing faster compare to when we hold the hammer at the bottom of the handle. Let say one holds the bottom of the handle(12 in long) of a 100g hammer vs one holds the middle of the handle(12 in long) of a 200g hammer. Do they...
  19. Manish_529

    Work done by gravity on a hanging chain?

    I tried taking an element of length dx and tried calculating the force of gravity acting on it so that I could just integrate over the whole chain, but I couldn't figure out what to do of that displacement part since the dx element is not moving as is just at rest (hanging). So, how should I...
  20. david3305

    Pulley system problem: 6 Pulleys and 1 Mass

    The following system is at rest with a block of mass m1 = 5kg, and a force F that is applied to the end of a string attached to the pulley system. Let g, the acceleration due to gravity equal to 10 (for simple calculations). My analysis is as follows: I'll first label the strings Tsub1 and...
  21. chwala

    What average power does the boy need to produce?

    In my approach, i have ##F_{Resolved} = 300 \cos 60^{\circ} = 150## Newtons. I also have, ... from ##v=u +at## ##2=0 +6a## ##a= \dfrac{1}{3}##. ##F=ma## ##F=30 ×\dfrac{1}{3} = 10## Newtons Therefore, ##P= \dfrac{(150+10) ×6}{6} = 160 ## W Insight is welcome...
  22. N

    Springs and Pulleys - Force analysis

    So I labelled all the springs from 1 to 4. Since the force is gradual, at equilibrium : ##F = k(x_2+ x_4) - - - - (1)## Now we need to relate the different extensions of the springs: ##kx_1 = kx_4## (same string) ##x_1 = x_4 (2)## ##kx_2 = 2kx_1## ( ideal pulley) ##x_2 =...
  23. P

    Tension Question for Ship Container and Wind Gust

    I tried a method solving for the force of the wind first which I found to be 2842.95 N. From there I found the torque force using torque = F_wind x d, where I let d = 90ft. This leads to a torque of 77987.8044 Nm. From there I used Tension = torque/moment arm, with a moment arm of 20ft (half of...
  24. A

    B I don't get instantaneous impulse

    I was reading this A-level mechanics book by L. Bostock and S. Chandler. The chapter was momentum and in it, there's a section about instantaneous impulse. It says "There are many occasions when a force acts for so short a time that the effect is instantaneous, example a bat striking a ball, in...
  25. S

    B 4 pounds over the weight limit of a tv stand

    I wanted to put a 39-pound tv on this tv stand: https://www.ikea.com/us/en/p/lack-tv-unit-black-brown-00566060/ The weight limit of top shelf is 35 pounds, but my tv weighs at 39 pounds. Is there any way I can adjust the force distribution so the shelf can hold my tv? tv has 2 base legs about...
  26. K

    Engineering Howe truss analysis using Ritter's method of sections

    I had made a silly inattention mistake. Once corrected everything worked out. I have updated the pictures to show the correct answer.
  27. yusungmagic

    Circular motion question: Mass on a rod rotating in a vertical circle

    By looking at the following question, I have no idea why the direction of force exerted by rod on a ball is represented like that. can anyone help me to understand?
  28. grade11studentgoaat

    Finding the direction of forces

    Tension force = 10lb[W] where do i put tension arrow in the full body diagram
  29. G

    Calculating Motor Force & Torque

    Hello All, I'm trying to figure out the above problem but don't know how to set it up and could use some help. For starting with the first question, I was thinking of doing PE = KE: PE = mgh = (10,000)*(9.81)*(1) = 98,100 kJ KE = 0.5m (v^2) = 0.5 (10,000)* (v^2) Sqrt(98,100 / 5,000) = 4.43...
  30. J

    Misc. Modeling Pressure in a Sound Wave Instrument with External Force

    Hello everyone, I’m working on a theoretical model for a sound wave instrument that involves a pipe. Traditionally, sound wave instruments utilize an open tube, but I’m interested in exploring what happens when I apply a force F to the pipe. How can I theoretically model the relationship...
  31. daisy7777

    Engineering Solving for the Reaction Force by taking Moment about a Point

    For this problem, I took the moment about point B to 'get rid' of the tension force in the cables BA and BC. By doing this, I figured I could solve for the x and y components of the reaction force at D. From there, I could solve for the tension in BA and BC in the x and y and then solve for Dz...
  32. V

    Coefficient of friction of a sandwiched body

    Consider a test setup as shown in Image below, where I have a blue object sandwiched between a material inside the container (for eg. sand) and a surface. The container is fixed and the material inside is assumed to not move. Using a force guage, I can measure the peak amount of force...
  33. S

    Pressure question: Weight of a car calculated from tyre contact patch area

    I tried 2 ways to solve it but both yielded different answers. i would like to know which is correct and why the other is wrong. thank you. method 1: consider force of each tyre. 5 x 10 = F = 50N. so 4 tyres = 200N = weight method 2: consider the whole car, total pressure = 4x5 = 20. total...
  34. M

    B "Accelerations" as higher order derivatives

    In physics, velocity (speed) is the "change of position (spacial location) per change of time" and acceleration is the "change of velocity per change of time". Mathematically this is first and second derivative. Do further derivatives exist that correspont physical quantities like "change of...
  35. A

    B Box being pulled up a slope with friction

    If I solve a problem of a box sliding down a slope or standing still on the slope, the force of friction is directed up along the slope. What happens if there is a force F pulling the box up along the slope, but it's unknown if it overcomes gravity and box is moving up or it only slows the box...
  36. T

    Engineering 2nd Degree Inderteminacy for Structure Using Force Method

    Dear all I am trying to find the support reactions on the following structure: The frame member in the horizontal is 8m long and in the vertical the member is 5m. To do this I am using the force method (or unit load method or virtual work method). Firstly, I removing the redundants at the...
  37. paulb203

    B Newton's Third Law Question -- Does the Earth Do Work on Me?

    When I do a press-up I consciously push down on the ground, my muscles tense, I breathe harder, I sweat, etc. When the Earth pushes back up on me (Newton's 3rd Law) is it 'doing anything', or does it push back up on me merely by virtue of it being there?
  38. A

    I Metal Ball Rolling in a Parabolic Bowl in the presence of a magnet

    I found this equation as a solution to the original problem of a point-like ball rolling without friction in a parabolic cavity from Lagrangian mechanics: Is it possible to add an extra force to this equation? I want to add a "magnet" at a certain position that will affect the ball. The...
  39. midiya

    B Is it possible to calculate how much force is exerted on the ground and shoe midsole by your body while you run?

    I believe it is not only about weight because you still push into the ground while you run, so it's gotta be more than that. I thought it could be calculated by a simple electronic scale experiment like you will push on them with your foot and collect the reading, however, it seems to be more...
  40. BurpHa

    Two Forces Acting Simultaneously

    I could understand the problem perfectly; however, I do not know how to construct the problem. The problem states that two forces are acting simultaneously on the object, but how could I represent that fact mathematically? I really want to solve it, but I am facing this roadblock, so please...
  41. S

    What is the relationship between tire size and pressure changes?

    a) ##P=\frac{F}{A}=\frac{\frac{1500\times 9.8}{4}}{180\times 10^{-4}}=2.04 \times 10^{5} Pa## b) Is the pressure in (a) gauge pressure? My answer for (b) is 2.04 x 10 5 + Po where Po is atmospheric pressure c) (i) it will increase since the size of the tire also increases (ii) I am not sure...
  42. S

    Energy of springs connected in series and parallel

    For P, the force will be 2F and the spring constant will be ##\frac{k}{2}## so the extension will be 4 times, and the energy will be 8E but there are no options showing 8E What is my mistake? Thanks
  43. N

    B Gravitatonal field force arrow diagram for Sun and Earth

    Hello, I am trying to get my head around this, maybe someone here can help. I have a force arrow diagram for gravitational forces of both Sun and the Earth. Can someone help me name these forces please. Am I correct in thinking that force 1 is the gravitational force that the Earth exerts on...
  44. F

    I What is the magnetic equivalent to the Coulomb?

    For electric charges the relation is ##F=k\frac{q_1q_2}{r^2}##, where ##k=\frac{1}{4\pi\varepsilon_0}##. It seems to me that for the (hypothesized) magnetic monopole one could write an equivalent ##F=n\frac{p_1p_2}{r^2}##. I have replaced the q's with p's for "pole strength", and k with n --...
  45. NikolasLund

    Friction force on a ball falling through a body of water

    I first attempted to solve the problem by ##A_{ext} = \Delta E_{mech} = F_{ext}s##. Here, ##F_{ext} = F_{friction}## and ##\Delta E_{mech} = E_{k2} + E_{p2} - E_{k1}##. We obtain then the following equation: $$F_{friction} = (m((v_2)^2 - (v_1)^2))/2h + mg,$$where ##v_1## is the velocity at time...
  46. A

    I [Q] Lorentz force in momentum conservation view

    Somebody, please explain to me about the Lorentz force between two parallel current-carrying wires in terms of the momentum conservation as the electromagnetic fields has momentum density. Especially, (1), If a short rectangular magnetic pulse due to an electric pulse in one wire will still...
  47. L

    I Not a physics major -- Question about how far we can kick an object

    Currently debating with friends how far varying weighed objects could be punted and the distance we could kick them. Instead of grabbing dumbbells I'd rather use math. Was looking for an equation to use and have been having trouble. I know the average adult can kick with a force of 1000lbs...
  48. H

    Explain why applying different forces to objects of different masses result in different accelerations

    I don't really get why applying different forces to objects of different masses would result in different accelerations. I read my textbook, and I understand the formula F(net) = m*a, and I think the reason may be because mass is inversely proportional to acceleration ? But this doesn't really...
  49. Sat-P

    Electromagnetic force on a positively charged particle

  50. Nabir14

    B Is there any physics topic explaining how objects break into parts?

    I am curious to know if there is any existing topic explaining how objects break into several pieces when force is applied.
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