Forces Definition and 1000 Threads

  1. A

    Finding vectors needed to cancel out given sets of forces

    Homework Statement For this assignment, I am given sets of forces and asked to solve for the force(s) needed to cancel them out. For this case, I am asked to solve for the missing parts of vectors A, B and C. I was only given vector C's Mass and Direction to start with, but I managed to get all...
  2. A

    Solve for vectors needed to cancel out given sets of forces

    Homework Statement For this assignment, I am given sets of forces and asked to solve for the force(s) needed to cancel them out. For this case, I am asked to solve for the last vector, which is vector D. I've successfully found its x and y component, magnitude, and mass (kg). I've also checked...
  3. I

    Is inertia the total gravitational forces of the Universe?

    Hi all I read a question on this subject from some time ago but was not satisfied with the clarity of the answer and in the light of recent experimental results I wish to clarify my understanding of this ancient scientific question. What is the cause of Inertia? So is inertia simply the total...
  4. T

    Understanding Tension on a Pulley

    Homework Statement Problem image: https://prnt.sc/gvhjso In this case I have to find the reaction forces at the point E (the Fx, Fy, and the Moment at point E) by using the given data. The 20kN forces at the load AC are concentrated, and are 1.8m far from each other. The tension of the cable is...
  5. yecko

    Net forces versus net moments -- solving a beam problem

    Homework Statement Homework Equations in photos The Attempt at a Solution [/B] First approach: Second approach: The two approaches used net force and net moment respectively in order to find reaction force of O, yet they got different answers. Why? Thank you very much!
  6. M

    What Are the Forces at Play in Antarctic Snowcat Towing?

    Homework Statement Two snowcats in Antarctica are towing a housing unit north, (an example is shown in Figure 4-50 on page 102). Snowcat A pulls at an angle 49 o west of north, and snow cat B pulls at an angle 31 o east of north. The sum of the forces FA and FB exerted on the unit by the...
  7. S

    I Stopping forces in an emergency stop

    Hi I'm trying to calculate the forces applied when suddenly stopping an object. I have a pair of winches which lowering an object at 400mm/s and would normally decelerate to a stop at 150mm/s^2. If the Estop for this winch is hit then we decelerate at 2000mm/s^2. However, if the power is...
  8. A

    Please explain the action of forces here

    Homework Statement Two forces are acting on a 4.87-kg object that moves with acceleration 5.47 m/s^2 in the positive y-direction. If one of the forces acts in the positive x-direction and has magnitude of 12 N, what is the magnitude of the other force in N? Homework Equations F=ma The...
  9. C

    Question Regarding Circular Motion and Normal Forces

    Homework Statement A roller coaster car has a mass of 500 kg when fully loaded with passengers. The path of the coaster from its initial point involves only up and down motion with no motion to the left or right. (A) If the vehicle has a speed of 20 m/s at the bottom of the first dip which...
  10. T

    B Electric+Magnetic Force Between a & b Charges: Inertial Frames

    Let's assume that a and b charges are moving. now in our lab frame there will be a electric+magnetic force whereas in a rest frame of either of the charges, there will be only an electric force. So, two inertial observers will measure different forces?
  11. E

    Door Rotation: The Influence of Attached Rods and Forces

    If I were to put attach a long rod to the side of a door (the exact opposite of the side where it is hinged, the slim part) And then I apply a force to the the right side of the rod I attached, would the door rotate to the right, or would the hinge completely oppose the force and the door...
  12. K

    B Relation between sum of the forces and energy

    In the picture above, there are three balls in separated small elevators. Elevator A lifts the ball upwards, elevator B stays still, elevator C moves the ball downwards, all in constant speed. (And this is a model, a simplification of the reality, we assume no other forces on the balls other...
  13. B

    Forces on a plane exerted by a ball

    Could someone please provide a diagram of all the forces acting on the plane, and explain why the answer is E? This is from the 2014 F=MA exam. Thanks, blueblast
  14. Eric Walker

    B Tidal effect in the balance of Coulomb and nuclear forces?

    In a heavy nucleus, the balance of the Coulomb and nuclear forces is a delicate one. This can be seen in two cases: First, in oblong deformed nuclei, alpha particle emission is more likely to occur at the poles, where the Coulomb barrier is thinner, than at the waist. Second, heavy synthetic...
  15. K

    Is the weight of an object exerted on another object?

    I have read on the internet that if an object rests on a table, that object will exert the force of its weight on the table. But, for some reason, that doesn't make sense to me. If I have a 10 kg book that rests on a table, the gravitational force on that object will be 98 N. If gravity is...
  16. C

    Forces on the slope of a triangular block

    Homework Statement I uploaded the question as an attached file. Homework Equations Fz = mg , F = ma , The Attempt at a Solution The slope : x Perpendicular to the slope: y I thought the Y forces can be neglected because the normal force counters the y component of the gravitational force...
  17. C

    Inelastic collision and the sum of internal forces

    Homework Statement Suppose I have a system which contains two bodies m1 and m2 with initial velocities v1 and v2 , respecitvely. they hurl toward each other and make an inelastic collision. such that they are now one body of mass m1 + m2 I know that the difference in momentum is...
  18. A

    I Can a plane escape Earth's gravity with a powerful engine and no air?

    If I drive a plane and the force of engine is bigger than force of gravity of it , if the engine is turn on always ,and assuming no air , will the plane continue moving up and escape from the gravity ?
  19. S

    How do I find Vector C in a non-right triangle using the Law of Cosines?

    Homework Statement Vector A: 1.96N at 20° Vector B: 1.71N at 65° There are different parts I did the graph part by hand. I am having trouble finding it analytically. We have to use cm for our triangle. Homework EquationsThe Attempt at a Solution Vector A: 1.96 cm at 20° Vector B: 1.71 cm at...
  20. D

    Determine the normal forces to hold an upside down cone

    Homework Statement With two fingers, you hold an ice cream cone motionless upside down, as shown in the figure. The mass of the cone is m and the coefficient of static friction between your fingers and the cone is μ.μ When viewed from the side, the angle of the tip is 2Θ. What is the minimum...
  21. X

    Calculating Unknown Forces in a Vector Diagram

    Homework Statement Hi, I'm having trouble with my first mechanics assignment and I'd appreciate some help. So, an object is being pulled using two ropes (Fa and Fb) with a resultant force of 970 N along the x axis. Angle from Fa to the axis is 20 degrees, angle from fb to the axis is 51...
  22. M

    Why does a ball move in your hand when net forces are 0?

    This is a more general and probably silly question, but if you have a ball in your hand and you move it upwards, the acceleration will be positive then after you move it at constant velocity, acceleration will be 0. However, how is net force is 0 when the ball is still moving? You are clearly...
  23. P

    Fictitious forces and artificial gravity

    I'd be extremely grateful if anyone could help me with this ... its mainly part iv) that I'm stuck on but the other parts build up to it! Thanks very much! 1. Homework Statement I have a wheel shaped space station of radius 100m rotating about its symmetry axis (defined to be the z axis) at...
  24. S

    Work energy theorem and forces at equilibrium -- Conceptual doubt

    A pendulum of mass m and length l is suspended from the ceiling of a trolley which has a constant acceleration a. Find the maximum deflection θ of the pendulum from the vertical. When I used work energy theorem, I got θ = 2 arctan(a/g). But when I took the equilibrium position and equated the...
  25. C

    Solving for the internal forces and reactions

    Homework Statement I'm having a hard time finding the reactions at the supports and the force exerted by the spring. Given: 20 lbs 25 lbs 35 lbs k = 200 lb/ft lo = 2.5 ft members are 4 ft longHomework Equations ΣM ∑Fy = 0 ∑Fx = 0 The Attempt at a Solution I tried solving for the reactions...
  26. H

    With which forces and why spring acts on two bodies

    Homework Statement Suppose we have spring which is between two bodies of different mass, with which force spring will act on every of them? Homework Equations Spring acts on a body with force kx The Attempt at a Solution A-/\/\/\/\/\/\/\-B Suppose body A has mass 2kg and body B has mass...
  27. D

    What forces contribute to a runner's forward propulsion?

    Homework Statement Homework Equations None. Only free-body diagrams I think, but I'm unsure how to exactyl draw it. The Attempt at a Solution So, my reasoning is that it is D, but I'm not exactly sure. When drawing a free body diagram, I only draw one force of friction, but I think...
  28. C

    How Does Biaxial Force Affect Stress and Strain in a Rectangular Bar?

    Homework Statement consider the rectangular bar undeformed a=b=2cm and c=20cm . The elastic modulus of the bar material is E=100 Gpa and its poissons ratio is u=0.3. The bar is subjected to biaxial forces in the x and y directions such that Fx=Fy=0.4x106 N and that Fx is tensile while Fy is...
  29. Pushoam

    Forces on Dielectrics: Understanding Griffith's Equations

    Forces on dielectrics I found difficulty in understanding this topic from Griffith. Here, while calculating F, in eqn. 4.61 , Griffith doesn't bother about energy stored in fringing field. So, even if I assume that there is no fringing field, then following the above procedure, I can say...
  30. C

    What are the new dimensions of a cube under biaxial forces?

    Homework Statement Consider the cube with sides a=b=c=10cm . This block is tested under biaxial forces that are applied in the X and y directions. Assume that the forces applied have equal magnitudes of Fx=Fy=2x10^6 and that the modulus and poissons ratio of the block material is E=2x10^11 Pa...
  31. M

    Forces of 3 charges in an equilateral triangle?

    1. The problem statement: in the first photo all variables and given/known data, Homework EquationsThe Attempt at a Solution : i wrote it all down in the second photo [/B]
  32. kmm

    I Understanding Conservative and Velocity Dependent Forces in Physics

    I actually have a few things I'm thinking about here. I'm curious as to whether a velocity dependent force field absolutely cannot be a conservative force field, in principle. I have at times come across statements in physics that I found out had mathematical exceptions for, but we don't...
  33. J

    Find the tension in the cable and reactive forces at ground

    Homework Statement A 160-kg utility pole extends 12m above the ground. A horizontal force of 250 N acts at its top and the pole is held in the vertical position by a cable, as shown in the figure (I have attached the photo). 1) draw a free-body diagram for the pole 2) Determine the tension...
  34. Alexander350

    Finding all the forces in this system

    Homework Statement [/B] I am trying to identify every force in this system and prove that it is in mechanical equilibrium when tan(θ)=⅓. Initially I had to solve it by finding when the derivative of potential with respect to θ was 0, but now I am just trying to resolve the forces. Homework...
  35. A

    I Can a 63mm Bore Pneumatic Ram handle the required weight at an angled position?

    Hey So I am still a beginner in Physics and work asked me today to calculate if a 63mm Bore Pneumatic Ram will do the required job. Anyway, so I know how to calculate the weight capacity the ram can handle if it is at a 90 deg angle however if the ram is on an angle then I am stuck. I need to...
  36. deuce123

    How Does Friction Affect Pulley Systems on Inclined Planes?

    Homework Statement A cord connected at one end to a block which can slide on an inclined plane has its other end wrapped around a cylinder resting in a depression at the top of the plane as shown in (Figure 1) . Determine the speed of the block after it has traveled 1.60 malong the plane...
  37. A

    Forces acting on a thrown object

    Homework Statement A ball with a mass of 200 g is thrown vertically upwards with an initial velocity of 16.0 m/s. It is allowed to fall back to its original position. Ignore air resistance. Calculate the force acting on the ball during its upward movement. Homework Equations w=mg The Attempt...
  38. A

    Alternative approach -- Bicycle on a curve

    Homework Statement A bicycle of mass m is traveling at constant speed v around a curve of radius r without slipping. You can take the acceleration due to gravity as g. Calculate the angle of tilt, θ, that will enable it to balance. Homework Equations R=mg Rsintheeta (Length)=Fcostheeta...
  39. W

    What Forces Affect a Motorcyclist's Cornering Performance?

    I have never studied any form of mathematics other than through 'getting through life' and working stuff out and trying to understand the mechanics/ physics in terms I understand. Non scientific / mathematical terms but words in English. I have a few questions I would like to ask a physicist to...
  40. V

    I Comparison of tidal forces acting on the Moon vs Enceladus

    I have heard about a moon Enceladus. Which is powered by tidal force. I suppose this force press back and forth on the moon and friction in the core causes heat. I hope I'm right :-) Now tidal force ##F_t=\frac{2GMmr}{R^3}##, where ##G## is Gravitation constant, ##M## is mass of planet causes...
  41. C

    Finding forces in members of frames

    Homework Statement I'm trying to solve for this problem below.How would you be able to get the force in member ID and GC? Find the reaction forces in member AFGH Homework Equations ∑M = 0 ∑[F][/y] = 0 ∑[F][/x] = 0[/B] The Attempt at a Solution I dismembered all of its parts but no matter...
  42. A

    How can two equal and opposite forces produce motion? [EM]

    I am having hard time understanding the definition of work done to move a charge in an electrostatic field book says that if charge A and B sitting at some position and now if I move the charge say A towards B from arbitrary direction that force required is exactly equal and opposite to the the...
  43. R

    Electrical forces, application of Colomb's law

    Homework Statement "In an early attempt to understand atomic structure, Niels Bohr modeled the hydrogen atom as an electron in uniform circular motion about a proton with the centripetal force caused by Colomb attraction. He predicted the radius of the electron's orbit to be 5.29x10^(-11) m...
  44. ibkev

    B Length Contraction: Real Compressive Forces?

    I'd like to get some conceptual clarification on whether or not length contraction is only apparent to an observer or if it's physically real in the sense that the object under contraction would experience compressive forces? My thinking on this has been along the lines of: I know that time...
  45. B

    How to Calculate F1 and F2 for a Balanced Beam?

    Ok here goes. It's been a long time since I've done anything like this and i just can't remember what to do. I'e got a beam 167.5mm long. It is supported at 24.5mm along the beam. 6600kgf acts at one end of the beam. F1 acts at 128.5mm along the beam. F2 acts at 167.5mm along the beam. F1...
  46. deuce123

    Solving Work & Forces Problems: Alpine Rescue Team

    Homework Statement You are a member of an alpine rescue team and must project a box of supplies, with mass m, up an incline of constant slope angle α so that it reaches a stranded skier who is a vertical distance h above the bottom of the incline. The incline is slippery, but there is some...
  47. G

    Calculating Forces on an L-Bracket for Supporting Large Pipework

    I am installing an L-shaped bracket into a brickwork chimney to support some large pipework. I am trying to work out the forces in each fixing to ensure that I won't be pulling the bracket off the wall once the pipes are filled with water. I've tried drawing the free body diagram and to resolve...
  48. deuce123

    Forces help -- 2 masses, a pulley and friction....

    Homework Statement Determine a formula for the acceleration of the system shown in the figure(Figure 1) in terms of mA, mB, and the mass of the cord, mC. Assume f to be the fraction of the cord that is hanging down between mB and the pulley, and μk to be the coefficient of kinetic friction...
  49. M

    B How is the Schrodinger Equation used in calculating forces of nature?

    First, if you want to refer to the Schrodinger Equation only.. is it only called Quantum Mechanics? Or does the word Quantum Mechanics also include Quantum Field Theory? If true. Then what words should you refer to the non-relativistic Schrodinger Equations only? About the forces of nature. The...
  50. deuce123

    Understanding Tension Forces in a Slowly Rising System

    Homework Statement How hard must she pull downward to raise herself slowly at constant speed? The mass of the person plus the bucket is 75 kg . The Attempt at a Solution Hey everyone, so I've answered this question and it equals too half her weight. W=2T, but i just want to intuitively...
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