Force Definition and 1000 Threads

  1. NeedFreedom

    I Gravity machine force calculations assistance needed

    Im prototyping a machine to lower liquid from a height using a chains and sprockets. Essentially liquid will fill at top, be lowered over a distance of 4.8 metres then emptied at bottom. The liquid needs to be lowered at a slow pace due to resistance on the output shaft, I am considering...
  2. M

    Buoyant force acting on an inverted glass in water

    My answer : According to the question, the glass and the air inside it entered the water. Let's assume that the net force becomes zero at a moment, that is, the sum of the weight force and F is equal to the buoyancy force. By going down in the water, the gas volume decreases, so the buoyancy...
  3. BurpHa

    What Is The Maximum Force The Locust Exerted on The Plate?

    At the beginning, I just looked for the highest point in the graph, which is approximately 90 \frac m s^2. Then I plugged it in the formula F = ma and got the force equaled to 0.045 N. However, when I looked back, the graph is about the change in acceleration. So really, I'm dealing with...
  4. M

    I How hard of a Hit force does it take to make a mass jump?

    I am looking for a formula that I can use to find out how high a steel rod or ball will jump up. If I hit mass M with force F how high will it jump up. If there is a program that would be great. every thing will be in pounds So if ball or rod of 10 lbs is hit on the bottem with 14 lbs of force...
  5. Ranku

    I Is the Coriolis Force a Real Phenomenon or Just an Illusion?

    Is the Coriolis force actually experienced by an object, or is the object simply deflected in its path?
  6. N

    Weird Thing About Coriolis Acceleration and Coriolis Force?

  7. Coldry

    The Force Of The Ladder Against The Wall

    OK folks, I'm sure this will be easy for the brains in this forum, but I've always been curious as to how this is done. So if you have situation where you have a ladder leaning on a wall and a person is some way up the ladder. If you know the length of the ladder (3m), the angle the ladder is...
  8. Spector989

    Variable mass, uniform body, force -- pulling a massive rope

    So i got some equations but i think i am missing something, my main doubt is what is the relation between dx / dt and v(o) [ here] . Workings in attachment
  9. Argonaut

    I Don't Ever Mention "Centrifugal Force" to Physicists

    I've just come across the following line while studying (Young & Freedman) and found it amusing. It sounds like a dirty family secret we discuss once and then should never mention again :biggrin:
  10. P

    Did I Miscalculate the Speed for a Leaking Cart Under Acceleration?

    My approach is to use the definition of the Force with ##\displaystyle F = \frac{dp}{dt} = \dot{m} v + m \dot{v}##. Since ##m(t)## decreases linearly, I should be able to set ##m(t) = M - \Phi t##, thus ##F = - \Phi v + (M - \Phi t) \dot{v}##, which gives ##\displaystyle v = -\frac{ F - (M -...
  11. H

    Solving for 'a' with Torque, Force, and Mass Moment of Inertia

    What I did was plug in the outer radius time the force into the torque and then the mass moment of inertia is equal to m*ro^2 so then I plugged in the mass times the radius of gyration squared into I and solved for a but this is not right.
  12. Spocktastic

    What is the Correct Angle for Tension Force in Arm Mechanics?

    I already solved for part a, setting the sum of the Torques of the arms and deltoid equal to 0 and subbing in values which lead to a tension force of 870N in the deltoid. For part b, I remembered the law of static equilibrium, so the summation x and y components of all the forces in the system...
  13. paulimerci

    How much force does the 20 kg block exert on the 10 kg block?

    The contact force on 10 kg due to 20 kg is taken as Fc2 m1 = 30kg, m2 = 20kg, m3 = 10kg F_A = Applied force μ = 0.15 Net force = mass X acceleration Fc2-Friction force = m3 X a, where a = F_A / (m1 +m2+ m3). Therefore the equation becomes Fc2 = m3 F_A/(m1+m2+m3) + μN = F_A/6 +15 I...
  14. T

    Engineering Determining Force and Directions on Truss with Pulley

    So far I have used methods of joints to determine the forces at point E, D, and C. However, there is also a pulley attached to point D and E which I included in the sum of forces, but I'm not sure if that's the correct way to apply them. Every force I've calculated so far has also been in...
  15. BurpHa

    A greater force? (A train engine pulling two identical cars)

    My choice is C, which is "equal to." Here is my reasoning: The engine pulls on car 1, so car 1 is having a force acting on it, which pulls car 1 forward. Likewise, the same amount of force is applied on car 2 by car 1 by moving forward with the same amount of force from the beginning. So it is...
  16. M

    Hop height of a rod and speed/ time if hit upward with force f

    I want to make a few of these if it will not cost a lot.
  17. M

    Is the Work Done by a Variable Force Non-Conservative?

    Can anyone tell me if my answer is wrong ?!
  18. K

    I Force required to pull a cruise liner or cargo ship

    I was wondering how much force is required to pull the Cargo ship using a Kite as shown in below image and specifications given in table? This picture is taken from a seawing aka airseas website. I do not know the water / air / skin resistance values or coefficients for the cargo. All I know...
  19. paulimerci

    For which case would the applied force be greater?

    If F is applied at an angle above the horizontal, it decreases the normal force and vice versa. So in case A, net force along X = F applied cos theta - friction since the object is moving with constant velocity, a = 0 and so the above equation becomes F applied cos theta = friction Now along...
  20. O

    Converting Force Measurement to Pressure

    I have a zip-tie like structure, which when pulled, squeezes an elastic part. Think of it like a having a zip-tie around your finger. I can measure a force that is related to the squeezing pressure. This relationship between force and pressure is quite linear. I would now need to create a...
  21. Z

    Elbow Flexion Joint Reaction Force

    Homework Statement:: This is not a homework, but I want to know how to find the joint reaction force of the 2d elbow flexion, if I know the angular acceleration of the forearm, and the mass of elbow with a known weight on hand. I assume the forearm is a simple cylinder. Suppose the angular...
  22. arhg

    A Normal force and force of friction inside a tube

    Dear all, Me and some colleagues (non-physicists) are discussing how force works when passing a cylinder (which we are holding) into a narrow tube. As we insert more of the cylinder into the tube, the force we are exerting is increasing. My theory is that the normal force is increasing and his...
  23. A

    Calculate the minimum force required

    I tried taking the components but got stuck there on what value of theta I should take
  24. G

    Analysis of a Figure to Calculate Force and Moment

    Figure: My attempt at a Solution: $$\overrightarrow{TFD}=TFD\dfrac{(-0,16\widehat{i}+0,11\widehat{j}-0,08\widehat{k})}{0,21}$$ View from above: We calculate ##D##: $$\sigma =90-\arctan \left( \dfrac{0,07}{0,240}\right)=73,74\, \textrm{º}$$ $$d=0,16\cdot \sin (\sigma)=0,1536\, \textrm{m}$$...
  25. samy4408

    I I found 2 formulas about surface tension -- which one is correct?

  26. G

    Tainter Damper Figure: Analyzing Forces

    Figure: Attempt at a solution: $$b=12\, \textrm{m},\quad H=8\, \textrm{m}$$ a) $$F_H=p_{CG}A=3767040\, \textrm{N}=\boxed{3767,04\, \textrm{kN}}$$ $$A=8\cdot 12=96\, \textrm{m}^2$$ $$p_{CG}=\rho_g h_{cg}=39240\, \textrm{Pa}$$ b) $$F_V=mg=\rho_g V$$ We calculate ##\theta \rightarrow 8=10\cdot...
  27. A

    Calculating Energy Dissipation for a Moving Object Using Integral Calculus

    Since ##F = -b * v## I said ## F(x) = -b*v(x) ## Also x(0) = 0 and x(T) = ## \frac{1}{3}aT^3 ## I made the integral ## ΔE = -b* \int\limits_0^\frac{aT^3}{3} v(x) dx ## I wanted to replace v(x) with v(t) somehow I first tried ##v(x) = ax^2## but then realized that was wrong Then I tried using...
  28. G

    Total force that a fluid exerts on a cylinder

    Figure: I have calculated the density of the cylinder: ##5479,0\, \textrm{kg}/\textrm{m}^3##. Attempt at a Solution: $$d=0,12,\,\, L=1,1,\,\, D=0,122,\,\, e=0,002,\,\, c=0,02,\,\, b=0,4,\,\, a=0,7$$ $$\omega =100\, \textrm{rpm}=10,472\, \textrm{rad}/\textrm{s}\quad e=0,122-0,12=0,002$$ We...
  29. J

    Hollowed out sphere exerting gravitational force

    I solved that the hollowed out mass is M/8, which is correct. I don't understand why it is incorrect to substitute the remaining mass (7M/8) back into the F = G*m1m2/r to produce the force. Why is the solution the force of the whole lead sphere minus the force of the “hole” lead sphere, which is...
  30. G

    Resultant force and centre of pressure in a tank

    Figure: a) CASE A ##\rightarrow p_a=101300\, \textrm{Pa}## $$F_{\textrm{res}}?,\,\, y_c-y_{cg}=y_{cp}$$ We find ##h_{cg}\rightarrow h_{cg}=3+h## $$h=0,75\cdot \sin (30)=0,375\, \textrm{m}\rightarrow h_{cg}=3,375\, \textrm{m}$$ $$p_{cG}=\rho_{H2O}gh_{cg}=33108,75\, \textrm{Pa}$$ We calculate...
  31. S

    Tetrahedron with 3 points fixed, and force applied to 4th

    My approach to this problem is to recognize that the tetrahedron being still means that net torque is zero and net force is zero. Fd is given Fa + Fb + Fc = -Fd Fa X a + Fb X b + Fc X c = <0,0,0> This can be split up into a series of 6 equations, 2 for each component. However, this is where I...
  32. FEAnalyst

    Gear teeth force from the rotation angle

    Hi, in books about machine design fundamentals, one may easily find the formulas for forces acting on the teeth of paired spur gears. They require torque as input. For example, for the tangential force: $$F=\frac{2T}{d}$$ where: ##T## - torque applied to the driven gear, ##d## - pitch diameter...
  33. dextercioby

    I Extending Newton's laws -- Is the concept of force still defined?

    It is argued that the correct interpretation of Newton's 2nd Law for one body of mass ##m## reads "The dynamics (i.e. vector sum of all external forces acting on the body = "all its interactions") dictates the kinetics (i.e. time derivative of the momentum vector = "motion")", under the...
  34. Crunge

    The maximal normal force (Friction with slanted surface)

    The problem that I immediately ran into was how I would calculate N without knowing Fmax. I didn't think the y-component of N would simply be the same magnitude as mg. After being stuck for a good while I even tested if it was, by dividing the magnitude of mg with cosθ, which of course ended up...
  35. Idontknowhatimdoing

    Normal force at the top of a vertical loop -- Circular Motion Dynamics

    From the equation for centripetal force, I can see that the centripetal force is proportional to v^2. Does this have something to do with why there is a normal force at the top? Does the velocity of the object require there to be a normal force? If so, why is that the case?
  36. S

    How to find minimum possible mass

    Unfortunately, this is not the right answer.
  37. Elementard

    Force of spring equation problems

    m=6.00Kg K=145N/m a=1.80m/s Fp=Fs ma=-kx (6)(1.8)=-(145)x x=-0.0745m I’m just wondering why I see some people make Fs=kx instead of -kx? isn’t the force of a spring a vector?
  38. P

    Rolling mill force calculations

    Hi, I'm building a rolling mill for flattening out bits of steel and I'm trying to make sure it's not going to break. I know that with a 1500w motor geared down to 60rpm (2pi rad/s) i end up with 239Nm of torque. 239Nm working at a radius of 0.0375m gives 6369N of force generated at the edge...
  39. 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...
  40. K

    I Understanding Three Force: Definition and Application

    We define four force as one which satisfies : ##\mathbf{f}=m \mathbf{a}## where ##\mathbf{a}=\frac{d \mathbf{u}}{d \tau}##. The quantities in bold face are four vectors. Hartle pg 88 defines a three force as : ##\frac{d \vec{p}}{d t} \equiv \vec{F}## Where ##\vec{p}=\frac{m...
  41. F

    I Reaction force of and its relation to normal force and friction

    Hello, When we consider a block sitting on a surface, the gravitational force ##W## and the normal force ##F_N## are applied to the block. Both equal i magnitude and opposite in direction. We call the normal force the reaction force exerted by the surface on the block. Now we consider the...
  42. F

    I Distributed Forces and force density....

    Hello, Forces can be concentrated (when acting at a single point) or distributed (when acting over a surface or line). In the case of distributed forces, we can find the resultant concentrated force by calculating a surface or line integral of the force density ##f(x)## w.r.t. an area or length...
  43. M

    Calculating the force that a permanent magnet exerts on a particle

    Dear readers, I have a question regarding permanent magnets and the force they generate on particles, which is far from my comfort zone. I have the option on using two types of permanent magnets and with two different setups. Imagine that we want to attract small particles using the magnets...
  44. jaumzaum

    I Does the electrical force also respect the Kepler Laws?

    I was wondering if the electrical force, which is a radial force that depends on the inverse of the distance squared, also respect the Three Kepler Laws? If so, what will the constant for the third law be?
  45. Th3

    B What’s the necessity of the strong force?

    To put it simply: Why do we have the strong force? If the goal of the fundamental forces (in a heavily generalized sense) is to bring particles to a lower state of energy, how is the strong force participating to this? Could it be due to atoms being a very stable configuration? If this is the...
  46. S

    B Can gravitational force have influence on objects at infinitely long distances?

    Can gravitational force have influence at objects at infinitely long distance? Is gravitational force in the form quantum packets?
  47. babaliaris

    I Pendulum Tension Force -- How to calculate the full vector?

    Hello! I'm trying to understand how this pendulum works. I found this video that explains how to calculate the T force from the rope. He uses the preservation of kinetic and potential energy in order to find the magnitude of the velocity and then using Newton's second law, he calculates the T...
  48. N

    I How Do Magnetic Forces Differ Between Magnets and Wires?

    I understand the iron fillings become little magnets all pointing in the same north south direction similar to the spin aligned electrons in the permanent magnet. Similarly, a compass near a wire traces out the magnetic field lines ie North/South. My question is how do I reconcile the fact that...
  49. josephsanders

    I Tangential electric force at a surface

    Suppose you have an infinite plane of charge. If the surface charge density is uniform, would the tangential electric force always be zero, even if it is not a conductor nor static? My thought process for this is that if you look at each point charge and draw the electric field lines, then at...
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