torque

  1. EEristavi

    Torque generated by water flow

    I know that I have to calculate force that is generated by water. However, I do it wrong way. ## A = \pi r^2 ## ## v = \frac Q A = \frac Q {\pi r^2}## ## F = P t = mvt = ....???? ## - have problem with mass. and is it even correct way? if I can calculate F - its easy afterwards... ##\tau = F...
  2. K

    Show that the flywheel inside the train counteracts lean in a curve

    Summary: Consider a train carriage rolling along a curve that forms a left turn on the track. The carriage speed is directed along the y axis (into the plane of the paper) in the figure. The trolley will have a tendency to curl in the curve in the specified direction. A flywheel is inserted...
  3. Anak Soleh

    Does friction torque in speeding up = speeding down?

    On speeding up: τload - τfriction = Iαup On speeding down: τfriction = Iαdown If i substitute τfriction from speeding down to speeding up equation, i get moment of inertia: I = (τload)/(αup+αdown) But, is this allowed? Does friction torque in speeding up is equal to friction torque in...
  4. A

    Rigid object in equilibrium

    Here's the task: My attempt at a solution (I choose C as an axis): However, the textbook solution says D should be 58.8. What am I doing wrong?
  5. J

    Torque required at the wheels to accelerate a vehicle at a certain rate?

    I'm struggling to understand something basic here. If I have a just a wheel, with mass 10kg, and radius 0.25m, and I specify that the CG is accelerating linearly at 1ms-2, how do I calculate the force needed to do this? Using F = ma gives 10N, but using this value for torque calculation on the...
  6. A

    Torque: find the force necessary for a body to be in equilibrium

    The question doesn't specify whether we're talking about translation or rotational equilibrium, so I suppose it's both: In order for the body to have translational equilibrium: 60 N + F2 = 0 F2 = -60N However, in order to have rotational equilibrium: 60 N * 3m + F2 *8 m = 0 60 N * 3m - 60...
  7. A

    How to stop a steering wheel using an electric motor?

    Problem Statement: i have a steering wheel mounted on an electric motor, and i want to stop the driver from going beyond a certain angle. i can read the torque applied by the driver, and the steering wheel angular velocity as well. how can i stop the steering wheel, without sending it harshely...
  8. EEristavi

    Inertia & Torque

    Only problem I have is in calculating Torque I say: dT = R dF = R k g dm & dm = ##\frac m {\Pi R^2}## R dr d##\theta## However, in the solution I see that: dT = r dF = r k g dm & dm = ##\frac m {\Pi R^2}## r dr d##\theta## I don't get it: when taking the whole T (when I integrate), why do I...
  9. D

    Find the acceleration and the work done by a force pulling a spool?

    I already solved the first part, but according the my book, the answer isn't quite correct. This is what I did. Finally, I ended up with ##a=\frac{F(r-R\cos\alpha)}{Rm(\gamma+1)}##. But according to my book, the answer is ##a=\frac{F(\cos\alpha-\frac{r}{R})}{m(1+\gamma)}##, what am I doing...
  10. M

    Simple harmonic motion of a bar pivoted at one end

    Hi, I am unsure how to proceed with this problem. I believe that I can correctly calculate the frequency of the oscillations for a bar that is not suspended from a spring but I do not know how to take the effect of the spring into account. The answer given by my professor is $$...
  11. M

    Stepper torque calculation to drive a solid cylinder

    Hi All, I'm working on some design and apparently my physics expertise are getting rusty,i'd appreciate some help with the following:- I need to calculate the required torque for a stepper motor to rotate a solid cylinder with the following properties:- radius : 20cm height: 12cm density : the...
  12. B

    A question about magnetism that causes a wheel-loop to rotate

    This question is from 1977 AP Physics C so I suppose it would be clear enough, but I am confused about question c. Question a is easy (it rotates counterclockwise), question b too (Στ=6*rxF=6*r x (I*i x B)=0.06). Question C is where I am stuck. The diagram provided with the question looks like...
  13. Np14

    What is the tension force for this system in rotational equilibrium?

    The system is in rotational equilibrium and therefore experiences no net torque, meaning all individual torques must add to zero. τNET = 0 = FFTsin(θ)L - FgL - Fg(L/2) τNET = 0 = FTsin30°(0.6???) - (0.5)(9.8)(0.6) - (2.0)(0.6/2) My only problem (I think) is figuring out what the length L is...
  14. J

    Rotation of a Submerged Disc

    1. A 20-lbf disc with diameter 18" and thickness of 3" is held static while completely submerged in water. Upon release of a lock, the disc experiences a torque from a torsional spring that causes rotation about its center of mass along the x/y axis (think coin toss, not wheel). If the spring is...
  15. M

    Torque required to tilt 1200 kg mass?

    Object to be tilted = 1200mm diameter cylinder Cylinder height = 2.5 meter weight of tilting assembly = 1200 kg Cylinder is on platform which is "L" shaped and tilting point is on that corner of "L" as in attached image. Shaft diameter on which it is tilted id 63mm Angular acceleration = 0.05236...
  16. Isolde Wilde

    B Are angular & vertical velocity the same if the objects are connected

    think of a engine. it has a flywheel and a rod connected to it. a string had been totally wrapped around the rod and a mass is hanged from the very end of the rod. the system is in equilibrium. but as the engine starts to rotate, the rod with rotate as well and cause the hanged object to go...
  17. S

    Mounting arm torque?

    Hi there, I'm going to install same kind of short throw projector in multiple locations, with different wall materials. Projector has integrated wall mount arm (see picture). - How to calculate total torque affecting mounting plate top row screws? Some locations have plasterboard walls...
  18. J

    Diving Board Torque with No Mass Given For the Diver

    The board is 4m and has 2 supports: support 1 exerts 5400N and support 2 exerts 6000N before the diver performs the dive. Neglecting the mass of the board, what is the force on the board due to the weight of the diver? My attempt at this question: FS2 - FS1 = 6000 - 5400 = 600N But I'm having...
  19. R

    Tension and net torque in a cable

    1. Homework Statement In figure 12-34, a uniform beam of weight 500N and length 3m is suspended horizontally, on the left it is hinged to the wall and on the right end of the beam is a cable attached to support it. the cable is attached distance D up the wall from the hinge. The least amount of...
  20. brotherbobby

    Alpha Particle Scattering and angular momentum

    Statement of the problem : "Using the definition L = r ##\times## p, prove that the direction of L is constant for an alpha (##\alpha##) particle whose scattering is shown in the diagram below. " Relevant equations : We are aware that the scattering takes place via a central force F = F(r)...
  21. Jeviah

    Calculating frictional torque

    1. Homework Statement Hello, so I currently designing a centrifugal brake, I know how much torque it needs to stop etc just unsure of a few things. How would I calculate frictional torque? I understand that I can use the net torque to determine what torque is needed for equilibrium etc however...
  22. Tibriel

    Will a sliding box fall over when it stops?

    1. Homework Statement Not an actual homework problem but a discussion that came up in class while we were learning about torque. A tall box is sliding across a surface with friction f, mass m, and velocity v. What equations would you use to figure out if the box would tip over while sliding...
  23. Justin71

    Screw ball torque

    Hi I don't understand what Fa mean ? This the weight or no ? And i don't understand too why in the torque TL, we have an additional part with the preload, the internal friction coeff of preload nut ... What is it ? Thanks.
  24. C

    Bolt Tightening - Torque versus Tension

    Hi guys, Bringing myself back up to speed with bolt tightening, would really appreciate if anyone has some resources or answers to these questions: 1. The proof load for torque tightening, and proof load for tension tightening 2. Main advantages and disadvantages between the two 3. What is...
  25. S

    Torque of board problem

    1. Homework Statement A homogeneous board weighing 60 kgf lies on two supports as shown. Find the forces acting on the supports. 2. Homework Equations $$\frac{F_A}{F_B} = \frac{OB}{OA}$$ where ##F_A## is the force acting on the support on the left, ##F_B## is the force acting on the...
  26. J

    I Torque coordinate transformation

    Hi all, I am currently working on a creating a mathematical model of a longboard and am in need of advice. The pictures describe the sitaution. Side view Top view Back view The pictures depict a simplified longboard - the brown line is the deck and the black lines represent the...
  27. Tone L

    B Force exerted at the end of a beam

    Hi all. Please see image I created as reference to this question. I have a uniform rod which is fixed to a structure, at the end of the rod there is a point mass attached to it. I am trying to calculate the downward force (torque) made at the end of the rod where the mass resides. I want to...
  28. R

    Derivation: force on magnetic moment in magnetic field

    I am trying to derive the equation ##\vec{\Gamma} = \vec{m} \times \vec{B}##, where ##\vec{m} = I \vec{A}## is the magnetic moment, and ##\vec{A}## is normal to surface ##A##, from the Lorentz force law ##\mathrm{d}\vec{F} = I \vec{dl} \times \vec{B}##. For an arbitrary closed current loop ##C##...
  29. P

    I Torque for sharpening pencils with different diameters

    Hello guys, if i sharpen 2 pencils with 2 different Diameters (thin and jumbo), which one will have a higher torque ( while sharpening), thus make it harder to sharpen? Let's assume that the angle of the pencil tips are the same, both have same wood of same density, the push force is the same...
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