Force Definition and 1000 Threads

  1. MantisShrimp

    How much force can a truck seat back cushion absorb during a collision?

    I do not know much about this, please help. My truck seat back cushion is 2" thick. Truck A is ~5,700 lbs from google. 2011 f-150 super cab 6.5ft bed. Truck B is ~5775. 2015 GMC Yukon xl slt. If truck A is stopped and braked and truck B hits truck A going 45-55mph creating a force of...
  2. Lotto

    Why can we move the spring with constant speed when we apply a force?

    One solution is that if we move with the same velocity as the spring does, the initial velocity of the block will be ##v## and the final will be zero, so its kinetic energy will transform into a potential energy of the spring. I would also say that we can say that if we pull the spring, we...
  3. L

    Confused about resolving Tension and Weight

    Calculations with 1: T1sintheta + T2sintheta = W T1costheta = T2costheta Calculations with 2: Wsintheta = T1 Wcostheta = T2 These are not equivalent. Can someone point out the flaw in my logic? Edit: System is in equilibrium!
  4. biomajor

    Would one be pushing as much as their weight?

    Because one is effectively pushing in the same way as a chest press machine, wouldn't the work done be the same?
  5. E

    B Magnetic attraction force Question

    Other than the most simple school stuff of attraction, repulsion and "lines of force", I've never studied magnets. Hence this question. On the left we have a disc magnet diameter D attracted to a much larger lump of steel with force F (when there is no gap between)...
  6. D

    Conservative forces in circular motion?

    TL;DR Summary: The rigid object move around the circle with constant force how it possible the force
  7. SacCno

    B Help Scaling Gravity Simulation

    I'm trying to make a 2D game on Unity similar to Universe Sandbox 2. I currently am working with a star and planet, both with roughly the masses of the sun and earth respectively for comparison and at a distance of 31,000,000km. My current model uses Newton's formula for gravitational force (F...
  8. I

    Why do I keep getting friction coefficient as a negative?

    I mean, I know why I am getting that result(because acceleration is negative), and I know that is wrong butI don't understand how do I get the correct answer... m=5000kg Vi=10m/s -> initial velocity Vf=0 -> final velocity t=5s mi=?I first calculated acceleration(Vf=Vi+at -> a=-10/5= -2m/s^2...
  9. Venturi365

    Find the unkown tensions and masses in the situation below

    TL;DR Summary: I don't know if my procedure is correct in this excercise I've tried to solve this problem but I find my solution unintuitive and I think I might be wrong. First of all, applying Newton's Laws I calculated the value for ##T_1## like this: $$ \begin{align} \sum F_{x} &=0\\...
  10. Tesla In Person

    I Pulley question -- Three pulleys lifting a mass...

    Hi, I have this pulley question, i have to find the force F that needs to be applied to the string to keep the system in equilibrium. I found 150N. Is it correct? T_1= 300N and T_2=150N so F is 150N.
  11. U

    I Why Does a Glass Move Outward When Opening the Fridge Door?

    If centrifugal force dont exist why glass of water moves outward/toward me when I open fridge door? Glass of water moves out in relation to door and in relation to earth, so what force push glass out?
  12. H

    I Force of an Electron on a Potential Wall?

    I've been looking at a practice test for an introductory class in quantum physics, and I've found a really weird question. It asks for an estimation of the force that an electron exerts on the walls of a box of known length during a collision. This seems like an entirely nonsense thing to ask...
  13. Mike_5158

    Calculate force required to eject a sheet metal part from a die cavity

    How do I calculate the force required to eject a sheet metal part from a die cavity. Coefficient of friction: 0.35 Surface area: 521.26 mm2 Elastic modulus: 68.9 GPa Material: 3003 Aluminium Material Thickness: 0.7mm Any help would be much appreciated. Thanks
  14. S

    I Question: Interpretation of Current and Magnetic Field Using Relativity

    The current in a wire is said to produce a magnetic field and a force on a charge. It is said that the correct way to interpret the effect is because of relativity. So does that mean that that the most basic non-relativistic equations that offer basic calculations of the forces and fields are...
  15. tellmesomething

    Centripetal force direction confusion

    So far: I an having trouble in the FBD. I drew one completely opposite to one I found on google . in this image NORmal force is pointed away from the cyclist and centripetal force is pointed away from the centre . mine was the complete opposite am i wrong?
  16. U

    I Newton's 2nd law for an object in free fall

    From inertial frame, object in free fall has just one force mg. So Fnet=non zero, but acceleration =0, isnt this in "fight" with Newton 2law? Is object accelerating or not ? Can I say, yes object is accelerating but object dont "experience" acceleration?
  17. Memo

    How Do I Determine the Center of Mass in This Situation?

    OA*P_A = OH*P + OB*P_B ⇔ OA*P_A = ¾*OA*P + 2OA*P_B ⇔ 5*10 = ¾*0.4*10 + 2*P_B →P_B=23.5 →m2=2.35 (kg) My result doesn't match the answer hint, and when I change the rod's centre of mass to OH=1, it fits the answer hint. How do I determine the centre of mass in this situation?
  18. S

    Towing two stacked boxes up a ramp

    Answer is (a) F ≃ 675 (N); (b) F ≃ 859 (N) (c) v ≃ 2.2 (m/s).
  19. K

    Jackhammer on Vehicle Suspension, Unsprung Mass, Tire patch load

    Hello all, I wanted to know what would happen if I put a jack hammer system on the unsprung part of the suspension, I posted this on the engineering forum but couldn't get a complete answer. https://www.eng-tips.com/viewthread.cfm?qid=512117 Basically the argument was if the reaction would...
  20. mazia

    Questions Regarding a Cat Going Up a Ramp

    EDIT: I've finally found the solution, so here's what I did. First, calculate Work using the equation: (F-mgsin(theta))*displacement, where F=the force being applied by the push, theta is the angle of the ramp, and displacement is the length of the ramp. Now that you have the value for work...
  21. yashboi123

    Force exerted on block B by Block A when being pushed on a frictionless surface

    I was just wondering why you would do mB * a to get the force A is exerting on B instead of mA * a
  22. mazia

    Question(s) Regarding Magnitude of Force (Window Washer Problem)

    So, ignore the -0.72, I was just trying to see if I had a sign error (I then remembered magnitude is absolute value) but basically: Since the weight is 12.0N, theta is 53.1, and the coefficient of kinetic friction is 0.100, I just plugged those values into the equations above...
  23. K

    Need help calculating maximum stress in a bolted assembly

    Trying to calculate the maximum stress that would occur in the attached assembly... The assembly consists of a tube sandwiched between two plates that are bolted down to a larger plate with an M6 bolt. Each of the two plates have a 400N force acting on them which is perpendicular to the axis of...
  24. D

    I [Question] Calculating the force generated by a tarp hung between two walls

    Hi. I have a problem I'm trying to solve. I have a tarp that is stretched horizontally across two walls. The walls are 5.5m apart and 50m long. There is a pressure of 10mBar above the tarp pushing it down, making it sag about 0.15m in the center. I'm trying to calculate the force with which the...
  25. P

    Problem with when to use Force and Energy. What compresses spring/

    This is how I tried to do it, which is the most direct. The force that the mass exerts on the spring is mgsin(53). and I equated that to kx. and found x. but apparently, this is wrong and the teacher told me a different method. (ME)1=(ME)2 due to conservation of mechanical energy...
  26. Lotto

    What force is needed to push out this slab on the bottom of the stack?

    The picture is here: I understand that friction I need to overcome is ##5mg\mu##, but why do I need to accelerate the slab on acceleration ##g\mu##?
  27. Nova_Chr0n0

    Engineering Resultant Force and Direction using Parallelogram Law

    Picture above is the complete question. I want to ask about the problem where I would use the parallelogram method. Here is my FBD: I start off by computing the angle alpha: α + α + 105 +105 = 360 α = 75 degree After that, I now use cosine law to solve for the resultant force...
  28. D

    What is the Resultant Force from adding these two forces?

    when is apply the formulae of resultant force for the two equations the angles cancel out and I can't get any value for the angle when i add the two equations: R^=f1^2+f2^2+2f1f2cos(theta) squart3*R=f1^2+f2^2-2f1f2cos(theta)
  29. Ggb

    B Coulumb's Law at 1 light year distance

    Hi, What happens to the force when the particle are kept at 1 light year distance. I agree practically the force would be very weak because of inverse square law, theoretically what happens to the force?
  30. A

    I Calculating Force on a Golf Ball when Putting on a Level Green

    I'm looking for advice on how to calculate the force needed to putt a golf ball on a level green a certain distance. I currently have the mass of the golf ball (45.93g), distance (3.048m), and the rolling coefficient of friction using a stimpmeter reading. I have started by creating a free body...
  31. Jim Robison

    B Is Time a Fundamental Force in Physics?

    We all know the four fundamental forces in physics: gravity, electromagnetism, and the strong and weak nuclear forces; and there is now some discussion about a fifth, more obscure force involving muons. But I have a question; could the fifth force be something we deal with every day? Could it...
  32. N

    I Sound pressure and inverse distance law

    Hello, I am confused as to how to think about sound pressure and the distance from a sound source. Let's assume that a sound wave is omnidirectional and propagating away from a source in a sphere. We have the following two equations: Pressure = Force/Area Intensity = Power/Area Many texts...
  33. E

    Work done by non-conservative force while particle moves in circle

    I have to show that the force is non-conservative, i.e. that work done for the round trip ##\neq 0##. Rearranging the circle equation, I can say that:$$x = \sqrt {R^2 - y^2}$$$$y = \sqrt {R^2 - x^2}$$ Then I have:$$F_x = -\sqrt {R^2 - x^2}$$$$F_y = \sqrt {R^2 - y^2}$$ Now, as I understand it, I...
  34. S

    Determining Maximum Torque in a Truck and Forklift System

    This maybe complex and complicated - I know its going to be multi step. Please see attached picture. It involves velocity and weight and gravity torque force, pivot points.
  35. doconnor17dan

    Calculations for Hydraulic Jacks lifting a load

    This cylinder is connected by a pipe to the larger diameter jack cylinder on the right where pressure p2 acts on the piston which has an area A2 and is able to lift a load equivalent to the force F2. The piston area of the hand pump cylinder is 2.0 cm2, the piston area of the jack piston is 10.0...
  36. S

    I When Water acts like Glue (flat surfaces)

    Water like glue This topic could have more meaning on a chemistry forum. Firts of telling my doupt, i will inform you why i put this question. My goal is controlling an obejct more accurately. I notice that sometimes a solid with plain face on a wet surface is difficult to remove. Besides it...
  37. Nova_Chr0n0

    Correct approach in resolving a force into its different components

    I've already got the answer and the way to solve it (parallelogram), but I'm just wondering why I cannot use the technique I've learned in the lesson torque. Let's focus on the line AB, if I use what I've learned in torque, the components would be like this: To find the force component in...
  38. K

    Design of bolts - Influence of higher free length

    Hello all, In a recent discussion, I came across this question of influence of free length (or unthreaded length) in bolts in retaining the clamping force between the elements to be joined. Out of the two proposals in the attached pic., which one will keep the two plates clamped for a longer...
  39. Lotto

    How to calculate the wind force acting on a water drop?

    TL;DR Summary: I have a water drop falling with a constant velocity ##v##, since ##mg=\frac 12 C \rho S v^2##. Wind is blowing with a velocity ##u## only in a horizontal direction. What will be its force acting on the drop? I would use this equation ##F= \frac 12 C\rho S u^2##. When I want to...
  40. Lotto

    B How will object's velocity change when a frictional force increases?

    Let's say that the mass of the objest is suddenly bigger, so when I want to maintain the constant movement, my force must increase as well. But will the velocity have the same magnitude? I think that the velocity will be smaller, so if I want to have the same initial velocity, I must apply an...
  41. J

    B Force transition through spring

    We put object on weight ang get a mass. What would that mass be if we put a spring between object and weigt, so that the spring woul shrink to half its original size?
  42. Say17

    Calculating Tension in a System of Trolleys

    Hi all, To find out the tension. First I have to find out the a. 1. step F = ma F = (m1+m2) *a F = (1+3)*a F = 4*a F/4 = a F = 10N + 50 N F = 60 N 60/4 = 15 m/s^2 2.step T =( m1/ (m1 + m2)) * F T = (1/ 1+3) * 60 T = 15 N But the final result is 20N. Thanks for your help!
  43. Slimy0233

    I Force on Body Attached to Spring at Displacement x - A.P. French

    Source: A.P. French's Vibrations and Waves I do not recognize the first equation, can someone explain how it came to be? The reasoning behind it. How can force on a body attached to a spring at small displacement x be represented as ? I know recognize F = - kx (restoring force) I realize...
  44. sophiecentaur

    A How can a 'Principle' produce a 'Force'?

    In a collapsing star, the expression for what goes on is "degeneracy pressure". The way it's put is that the Pauli Exclusion Principle just doesn't allow more than one fermion to exist in one place (state). So the star reaches a certain volume and, on the way, produces a lot of Energy. I can...
  45. M

    Explanation for Newton II giving negative mass in my Physics lab results please

    I am trying to verify Newton II. The setup I am using is, Where ##m_1 = 0.887 kg## is a cart and ##m_2 = 0.02016 kg## is a small hanging mass. There is a force sensor on ##m_1## to measure the force acting on it from the string and the acceleration of the cart. To verify Newton's Second Law...
  46. H

    Calculation of Box's Acceleration on a Trailer with Friction

    Question picture: My solution: Where: S is the lineforce Ff is the force as a result of friction a is the resulting acceleration F is the acting force The answear is supposed to be a=(F-2mg(mu))/(m+M) Any idea what i could have missed? Thanks for your help on beforehand!
  47. Mohmmad Maaitah

    Deriving force from momentum using d(mv)/dt

    How did the d(mv)/dt become the other two? Can someone explain how do we derive for new formulas in physics?
  48. paulimerci

    Find the magnitude of the electric force from 3 charges at vertices of a cube

    There are three charges with +1 μC and −1 μC, are placed at the opposite corners of a cube with edges of length 1 cm, and the distance from P to B is 1cm 2. I labeled them as A, P, and B, which is shown in the diagram below. Since we need to find the magnitude of the charge at point P and the...
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