Force equation Definition and 70 Threads

  1. D

    Solving for Tension in Net Force Equation: Need Help!

    I have tried finding the tension of the string through the equation Net Force = T - mg = ma but I am struggling with coming up with the correct acceleration. Is my net force equation correct?
  2. C

    Conservation of Energy with Mass on Hemisphere

    I tried approaching this question like this: F_N - mgcos(theta) = -mR(theta_dot)^2 and theta_dot = v/R since R is constant F_N = m(gcos(theta) - (v - v_0)^2/R) (with v being final velocity and v_0 being the initial velocity from the impulse) and then using energy conservation: at t = 0: E =...
  3. theanswer2physicsisu

    Force and Kinematics -- Accelerating a 10kg box vertically

    I realize that there is a downward force of gravity weighing the object toward earth’s surface, equaling F = mg (downward). The upward force would have to be something at least as much as the downward force in order to lift the object up ”such that it is accelerated from rest to a velocity of 5...
  4. S

    I Gravitational force equation derived from GR

    Hello everyone, I know that GR equations are complicated and beyond my scope. But does GR give a simple gravitational equation: Force (as we know it) as a function of distance? (without any complicated tensors). - If yes. What is the equation? Does it give us something similar to Newtons...
  5. G

    I Lorentz Force Equation: Coercion & Maxwell Stress Tensor

    When deriving the Maxwell Stress tensor, the Lorentz formula is converted from point particle: F=qE+qv x B Into current and charge density: F=ρ E + j x B However an argument can be made that we can't "fieldify" both q and E at one step, and thus, a "coercion" of the field to a value is...
  6. 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...
  7. E

    Force equation: use mass or weight?

    I require to calculate acceleration of an object caused by a force of 100N acting upon it. The weight of the object is 0.5kg I'm using the equation F = m * a Is it correct to use weight of the object instead of mass in the equation. Will it yield correct results? Or would I need to calculate...
  8. Protea Grandiceps

    I X variable in damping force equation for damped oscillation?

    Hi, for ease of reference this posting is segmented into : 1. Background 2. Focus 3. Question 1. Background: Regarding (one, linear, second-order, homogeneous, ordinary, differential) equation describing the force in a non-driven, damped oscillation: F = m.a = -k.x - b.v F =...
  9. D

    I Calculating S Using Fm in a Magnus Force Equation

    what is s in this equation and how what equation do I need to figure out what S is Fm = S (w × v) Where: Fm =the Magnus force vector w= angular velocity vector of the object v=Velocity of the fluid (or velocity of object, depends on perspective) S= air resistance coefficient across the...
  10. Z

    Solve for x(t) and v(t) given a Force equation using Mathematica

    Homework Statement Homework Equations F= ma or F= md^2x/dt^2 The Attempt at a Solution I know that this second order differential is non linear. I attempted to solve the problem as -k/x^2 = md^2x/dt^2 but I'm getting trouble since it is a second order ODE and I haven't learned how to solve...
  11. G

    Identifying Multiple Oscillations in a Graph

    Homework Statement Two masses (M1 and M2) are connected together by 3 springs. The spring constants are k1, k2, k3. Block 1 is at equilibrium at x=0. Block 2 is at equilibrium at x=1. Determine a function for the force on the blocks. Homework Equations The Attempt at a Solution [/B] Without...
  12. Beth N

    Writing Force equation in terms of pressure and area

    Homework Statement Problem 16.39 [/B] The viscous force of a liquid in laminar flow through length L is given by ##F_v=4\pi\etaL v_m## where ##\eta## is liquid viscosity and ##v_m## is maximum velocity of the fluid. Find an expression for ##v_m## in terms of p1, p2 (pressure at each end) and...
  13. K

    Particle with mass m and force F(t). Show that x = x(t)

    Homework Statement A particle of mass m is initially at rest at x = 0. It is acted upon by a force F = A cosh (\beta t) (1) A) Show that at very small values of t, the position is approximately given by x(t) = \frac{1}{2}\frac{F_0}{m}t^2 (2), where F_0 is the force at...
  14. MattNguyen

    Potential energy equation to force equation?

    Homework Statement The binding potential energy in a diatomic molecule (N2 for example) is often approximated by the Morse potential energy which has the form U(r) = De (1-e^[-a(r-re)])2 where De is a constant that reflects the well depth (dissociation energy), a is a constant that reflects the...
  15. Peeter

    Magnetostatics force equation for continuous current density

    In Jackson, the following equations for the vector potential, magnetostatic force and torque are derived##\mathbf{m} = \frac{1}{{2}} \int \mathbf{x}' \times \mathbf{J}(\mathbf{x}') d^3 x'## ##\mathbf{A} = \frac{\mu_0}{4\pi} \frac{\mathbf{m} \times \mathbf{x}}{\left\lvert {\mathbf{x}}...
  16. R

    Force equations: Force on ground by angled supports

    Homework Statement [/B] P=60kN angle alpha = 45 degrees angle beta = 20 degrees The task is to calculate the force on the base A and C, and to draw vectors that represent those forces. Homework EquationsThe Attempt at a Solution I did similar examples at the class, but when I had to do this...
  17. A

    How to calculate force exerted by ground

    Homework Statement Force exerted by the ground on the rocket Mass of the Rocket = 1500kg Duration of landing impact = 0.04 s Velocity at time of impact = 175 m/s Distance traveled = 30km Time taken to complete journey = 6 minutes Acceleration due to gravity = 9.8 m/s^2 Homework Equations...
  18. P

    Verify Sol. of an Dynamic Problem with 2 Wheels

    1. The problem is the following: Starting from stillness @ t = 0, we are looking for the acceleration @T=0 of the 2 wheels (rolling without slip, in particular in point P4 we have a gear wheel contact so we can have that the reaction R2y of the plane could be also in direction y2, in this case...
  19. T

    I Is F = ma the generalized force equation?

    It just seems odd that the force on an object goes based on the second time derivative of its position vector. I understand that this is what is observed through experiment, but is this only for certain types of situations? Is the acceleration only some kind of low-order approximation of a...
  20. S

    Solving Impact Force Equation: Tips & Explanations

    Hello, I have been turning to this subject and tried to develop the right equation on my own. What I did was: mgh = ½kx2 (fall energy = spring energy) x2 = 2mgh/k (obviously devided by ½k) sqrt(2mgh/k) = x (taking out square root) F = mgh/x = mgh/sqrt(2mgh/k) = sqrt(½mghk) (energy /distance...
  21. H

    How can I write out the full equation for the Electroweak Force?

    I am currently working on presenting a poster for my science project on the Electroweak Force and I wanted to show on my poster the full equation. I read the Wikipedia page on the Electroweak Force and found the equation, but I'm not sure how to represent it fully. Can someone please help me by...
  22. D

    Are the Forces in These Equations Different?

    Are two forces in the equation different forces? I heard the force in the second equation is like impulsive force. The concept is nebulous to me can someone also elaborate further? f=ma f= mxΔv/t
  23. shanepitts

    Finding time required via force equation

    The problem, relevant equations, and my attempt at a solution are all shown on both attached images. Not sure where the π and and extra (1/4)1/2 is coming from. Also, I noticed that my final result, in the attemp at a solution should be t=(mb3/4k)1/2, no negative sign.
  24. A

    Velocity frame of reference in lorentz force equation

    Hi, I am new here, but there is a question that really bugs me :-(. In Lorentz force why was the velocity defined as relative to the observer and not relative to thesystem generating the magnetic field. By defining it relativ eto the system relativity is not needed to explain how an observer...
  25. V

    Using Lorentz Force Equation to find kinetic energy of a particle.

    Homework Statement A charged particle (m=1.673*10^-27 kg) exists in a region with E=10 kV/m in the x direction and B=1T in the y direction. If the particle moves without being deflected calculate its kinetic energy. Homework Equations F=Q(E+u x B) and KE=1/2 mu^2 where u is velocity. This is...
  26. G

    Given a force equation and mass, find velocity

    Homework Statement The force on a particle of mass 3.0 kg moving in one dimension at time t, is given by: F = 9.0 +2.0t - 4.0t2. What is the velocity of the particle? (Let v0=0 and ti=0)Homework Equations [/B] I know to use F = ma for sure. And I believe this is the motion equation I...
  27. M

    Finding Work from Force Equation

    Homework Statement Homework Equations W = F*d The Attempt at a Solution a. W = Ce^(ax)*2a^-1 b. W = Ce^(ax)*2a^-1 c. w = Ce^(ax)*(-4a^-1) I feel like this problem is more than just this simple...
  28. P

    Solve relativistic differential force equation for velocity

    Homework Statement I proved that a relativistic 1D force is F = \gamma3*m*dVx/dt = m * dVx/dt * 1/ (1 - (v/c)2)3/2 Then, "This is a separable differential equation that can be solved using a trig substitution. Use this (or some other technique that works) to show that the velocity is given...
  29. X

    Drag Force Equation: Sphere vs 1/2pv^2C_dA

    Homework Statement Hi, i have a peculiar question after watching MIT lecture:http://ocw.mit.edu/courses/physics/8-01-physics-i-classical-mechanics-fall-1999/video-lectures/lecture-12/ What is the difference between the equation representing the drag force for a sphere...
  30. T

    Why is the frictional force equation F = μN not equal to F = mg(cosθ)?

    Why isn't the force of friction F= (frictional constant)(force of gravity)? Since F = mg(coefficiant) and g is negative denoting the direction of the vector, gravitational force.
  31. F

    Frictional Force Equation Doesn't Make Sense

    Frictional Force is mathematically defined as: Ff = μ*m*g*cos(θ) , where μ is the coefficient of friction, m is the mass of the object, g is the acceleration due to gravity and θ is the angle of the inclined plane. But in terms of direction, this makes no sense! Suppose there is an...
  32. M

    Extending the Lorentz force equation to accommodate SR

    I would be very grateful if someone would kindly explain this generalization of the Lorentz force law to the special relativity domain. I am not entirely sure if what I have jotted down is exactly as the speaker intended to convey. But here is what I have got. Please bear with me...
  33. K

    Finding maximum bending moment when shear force equation is known

    Homework Statement Calculate the Maximum Bending Moment of the bridge section using the values given. Ra = 61837.91667 N Rb = 78304.5833 N (please refer to attached diagram) Homework Equations shear force is = 0 when x = 13.755998 m (I worked this distance and the shear force equation out...
  34. H

    Deriving Force Equation from Scaling Law

    Hi. I am reading this chapter about dimensionless ratios and scaling law. and it says like this: \alphaF = \frac{Fp}{Fm} = \frac{ρp . Vp^2 . Lp^2}{ρm . Vm^2 . Lm^2} (1) From this, it is obvious one can write for these forces: Fp = C\frac{1}{2} ρp Vp^2 . Lp^2 (2)...
  35. PolywellGuy

    Why the magnetic moment not included in the Lorentz Force equation.

    A charged particle - like an electron - has a magnetic moment. This moment changes depending on where the electron is. If you apply a magnetic field to an object with a magnetic moment, it experiences a torque. It turns. This turning motion is not included in the overall motion of the...
  36. H

    How can the required force be calculated for pushing a block up an incline?

    Homework Statement as a new physics student, I'm not sure how to derive the formula i need to answer this question. there's a ramp that rises 1m in height and 20m in length. a block weighing 20,000kg needs to be pushed up it. (yup, we're building the pyramids). how much force is needed to...
  37. J

    Non-linear force to linear force equation

    I need to design a cam based on the following math problem: A non-linear force f(n) is working on a lever that is x + x' long (x+x'=constant). I need an equation for the ratio, x/x', such that the counter-balancing force, f', is constant (non-varying). By varying the ratio of f(n) to f', that...
  38. N

    Finding the coefficient of static friction in a centripiton force equation

    Homework Statement a bus passanger has her laptop sitting on the seat next to her while the bus moves at 10m/s, the bus goes around a turn with a radius of 25m. what is the coefficient of static friction in order to keep the laptop from sliding? Homework Equations The Attempt at...
  39. E

    Verifying Diff. Force Equation for System: Can You Help?

    Homework Statement Hi, i need to write the differencial force equation for the system attached, and i am not sure if what i do is right. when: F- externa power m1,m2 - mass x1,x2 - mas location The Attempt at a Solution This is what i got: for m1: F-k*(x1-x2)-D*(x1'-x2')=m*x1''...
  40. D

    Development of Magentic force equation to include angle

    Hi All, B = μonI I am trying to adapt this formula to include a dependence upon the angle made by the coils relative to the cylindrical core of the electromagnet. For example it is known that the number of coils (n) that can be formed around a cylinder should be dependent upon the length of...
  41. B

    Given force equation, solve for work.

    Homework Statement Assume that a force acting on an object is given by , where the constants = 2.9 and = 3.9 . Determine the work done on the object by this force as it moves in a straight line from the origin to = (10.0 + 21.5). The Attempt at a Solution well... what i did first was i...
  42. J

    Problems with the Force equation

    Ok I've been trying to figure this out for some time now We all know the formula F=ma now acceleration is measured a=(v-v0)/t now if there was an object in motion (lets say we measured the speed of a vehicle moving in a straight line at a constant speed of 10m/s over 30 seconds) this gives...
  43. L

    Using a Force equation to find out how much WORK is done.

    Homework Statement A 2.0 kg block is acted on by the following force Force=[(2N/m)x-(5N/m2)x2]{ihat}+[(13N/(1/m2)x2-(6/m)x+7)e-x^2/(2m^2)cos{(2∏)x/3m}]{jhat} as the object moves horizontally along a surface. In the expression for the force, x indicates the position of the block along the...
  44. C

    Need help finding μ in Frictional Force equation

    Homework Statement A crate with a mass of 25 kg is on a ramp that is inclined at an angle of 30o from the horizontal. An applied force of 35 N directed parallel to the ramp is used to pull the crate with a constant speed up the ramp a distance of 15 m. What is the work done on the crate by...
  45. C

    Exploring the Magnus Force Equation

    Hey everyone, I was researching the magnus force and came upon the equation being: Fm= S(w x v) where S is the air resistance coefficient and (w x v) is the cross product of the angular velocity and the velocity of the object. Well my question is that if the drag coefficient is...
  46. X

    Find work given force equation in component form

    Homework Statement First, there is a graph showing x initial at (0,0) and x final at (1,1) Given: F = xy i +xyj Find the work done by this force moving the particle from x initial to x final. [note you'll need a relationship between y and x] Homework Equations W = Fdcos(theta)...
  47. N

    Calculating Components of Force: Understanding the F1 = 97g@338 Degrees Equation

    Hello guys, I just have a simple question and I hope it doesn't get deleted or anything but anyways... The question is, "If F1 = 97g@338 degrees, then its components are?" Then in my book it gives me three answers and I have to pick the correct one... A: F1x = 29g, F1y = 93g B: F1x =...
  48. MysticDude

    How Do You Calculate Net Force on a Block on a Ramp?

    Homework Statement Write the equation used to calculate net force on a block of mass m that is accelerating down a ramp. Homework Equations The Attempt at a Solution Okay I think that we are going to have to use the equation F - f = ma. Since the question says to find the net...
  49. G

    How Do You Calculate Work from a Force Applied at an Angle?

    Homework Statement A force is applied to a block downwards at 30 degrees above the horizon line. the Force = x^2 - 2x (Newtons). Find work over the first 2 meters Homework Equations Work = integral(F(x)dx) Work = integral(Fcos(theta)dx) Work = F(x)delta(x) The Attempt at a...
  50. J

    Green's Function for Newtons Force Equation

    This isn't so much a problem as a step in some maths that I don't understand: (I'm trying to follow a very badly written help sheet) Here's how it goes: Given Newtons equation m \ddot{x} = F The Green's function for this equation is given by \ddot{G}(t,t^\prime)=\delta(t-t^\prime) (1)...
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