Rod Definition and 1000 Threads

  1. P

    Rod shortening - physical reality?

    Hi Guys, I seem to have gone in circles YET AGAIN! When discussing the expansion of the Universe I was told by friends that masses and objects do not expand with space because the forces within the mass are so much stronger than the inflationary force. When discussing General relativity we...
  2. A

    Conducting Rod in Electric Field

    If an uncharged conductor, a metal rod say, is placed in a uniform electric field E, parallel to the field (see figure), does it develop a potential difference between its two ends? If so, how is the potential difference related to the field E?
  3. F

    What is the integral of a thin rod's electric field?

    Homework Statement We have a thin rod of length 10 cm uniformly charged with a total charge of + 40 nC . A small glass bead charged to + 6 nC is located 4 cm from the center of the rod. What is the force on the bead? Homework Equations E = integral of K dq /r^2 and Q = lambda L and...
  4. D

    A neutral metal rod in a uniform magnetic field

    Homework Statement A neutral metal rod of length 0.35 m slides horizontally at a constant speed of 9 m/s on frictionless insulating rails through a region of uniform magnetic field of magnitude 0.6 tesla, directed into the page as shown in the diagram. Before answering the following...
  5. J

    Calculating Mass of a Long Thin Rod

    Homework Statement A long thin rod lies along the x-axis from the origin to x=L, with L= 0.750 m. The mass per unit length, l (in kg/m) varies according to the equation l = l0 (1+1.110x2). The value of l0 is 0.500 kg/m and x is in meters. Homework Equations stated in equation The...
  6. L

    Calculating electron mobility in a rod

    Studying for final, this is one of the suggested questions, I have no idea how to approach it. Homework Statement A cylindrical aluminum rod of 2 mm in diameter and 5 cm in length has a thermal conductivity of 237 W m-1 K-1 at 300 K. Calculate the electron mobility in the rod if aluminum...
  7. C

    Faraday's Law: Conducting rod moving across a magnetic field

    Homework Statement A conducting rod is pulled horizontally with constant force F= 3.40 N along a set of rails separated by d= 0.260 m. A uniform magnetic field B= 0.500T is directed into the page. There is no friction between the rod and the rails, and the rod moves with constant velocity v=...
  8. Q

    Kinetic energy of a rod in a circle

    Homework Statement Suppose that we have a uniform rod inside a circle. It's free to slide with its ends on the inside of the circle, and it subtends an angle of 120 degrees at the center of the circle. I'm looking for the Lagrangian of this system. Homework Equations I = ml^2/12 for...
  9. N

    Salt deposit deterrance by Magnesium rod

    I recently repaired a domestic water heater and had to replace the heater element that was heavily coated with hard water salts as well as the SS (Stainless Steel) tank had a large quantity of salt precipitate; the heater element has the option to have a magnesium rod/ element placed/ coupled...
  10. S

    Angular velocity of a falling rod?

    A uniform rod of mass 0.62 kg is 6 m long. The rod is pivoted about a horizontal, fric- tionless pin at the end of a thin extension (of negligible mass) a distance 6 m from the cen- ter of mass of the rod. Initially the rod makes an angle of 48◦ with the horizontal. The rod is released...
  11. R

    A rod with two balls on each side - what do the scales on each side show?

    Homework Statement There's a rod, 1 m long and by itself weighing 1 kg, with two balls attached at each of the sides, one weighing 2 kg, and the other 4 kg. The balls are put upon two scales. What force is applied upon each of the scales (e.g. what do the scales show)? Homework Equations...
  12. F

    Force of Pulled/Pushed Rod: What's the Difference?

    Rod is 1. pulled, 2. pushed horizontally. Force required to sustain constant vel.? Homework Statement There are 2 scenarios. 1. A rod of mass 5kg is first pulled at constant velocity by a force at 45° to the horizontal. 2. Then the same rod is pushed at constant velocity by a force at...
  13. D

    Magnetic field of a charged rod

    moving charged particles created a magnetic field perpendicular to their motion I believe. Anyways If you where to give a metal rod a positive or negative charge and spun it really fast would you created a noticeable magnetic field as a result of the moving rod as a whole? Its just a thought...
  14. M

    Calculating Force on a Rat Attached to a Spinning Rod: Physics Homework Solution

    Homework Statement A wooden rod of negligible mass and length 77.0 cm is pivoted about a horizontal axis through its center. A white rat with mass 0.480 kg clings to one end of the stick and a mouse with mass 0.180 kg is placed at the other end of the rod (the end away from the rat), and the...
  15. S

    What are the Rotational Dynamics of a Thin Rod Held by a Pivot Point and String?

    rotational dynamics rod--please help! Homework Statement A thin rod of length l and mass m is fixed at a far ends by a free pivot and held from rotating with a string attached at 3/4l and fixed toa ceiling. The moment of inertia of a thin rod about a far end is ml2/3 a) what is the pivot...
  16. S

    A heavy rod AB is suspended from a point O by two strings OA and OB .

    A heavy rod AB is suspended from a point O by two strings OA and OB . Show that the plane OAB is vertical. How to do this? Please help me.
  17. K

    Positively charged plastic rod of length L

    Homework Statement The figure shows a positively charged plastic rod of length L = 2.40 m and uniform linear charge density 8.00×10-3 C/m. Setting V= 0 at infinity, find the electric potential at point P for d = 1.536 m. Homework Equations The Attempt at a Solution Alright, I...
  18. D

    What Is the Electric Field Near a Charged Rod?

    Homework Statement If the total charge on a rod of length 0.4 m is 2.6 nC, what is the magnitude of the electric field at a location 1 cm from the midpoint of the rod?Homework Equations [(2QK)/(Y)](1/sqrt(L^2 + 4[(Y)^2]), K = 8.99E9 I don't know if the above equation is actually correct.The...
  19. J

    Rod Pendulum (high school circular motion)

    Homework Statement A rod of mass m and length L is suspended from one end, and swings as a pendulum (ignore friction from the hinge). It is released from rest when it forms an angle θ with respect to the vertical. The moment of inertia of the rod about its rotation axis is mL2/3. What is...
  20. Z

    How Large Is the Force on a Rod Partially Inserted in a Solenoid?

    Homework Statement A long cylindrical rod (permeability u , length L0, radius R) is partially inserted into a long solenoid (length L1, radius R, turn density n, and fixed current I) How large is the force on the rod? Our hint is to first calculate the total energy in the field...
  21. P

    What Are the Normal Mode Frequencies of a Rod on a String?

    Homework Statement A uniform rod of length a hangs vertically on the end of an inelastic string of length a, the string being attached to the upper end of the rod. What are the frequencies of the normal modes of oscillation in a vertical plane? Answer: \omega^2 = (5 \pm \sqrt{19})g/a...
  22. T

    Falling rod, collision, angular velocity

    Homework Statement A thin, slender rod with mass m and length L is held in a vertical position, the height h over a solid table. The rod is dropped and the end of the rod strikes the corner of the table. The rod begins a rotation around the corner. a) Is linear momentum conserved...
  23. M

    Increase of radius of circular rod due to torque

    Homework Statement I am trying to understand how will the radius of a circular beam grow when a torque is applied. There is a beam with length l, radius r, and a moment M1 applied on it. Its radius will grow with dr. What is the Young modulus of the beam? M= 15 N m r= 0.008 m l= 0.2 m...
  24. S

    Electric Potential Energy of a Rod

    Homework Statement There is a thin rod of length L that carries a uniform charge per unit length \lambda. Starting from the expression for the potential of a point charge, derive an expression for the electric potential V (y) at a distance y away from the centre of the rod on the axis (y) of...
  25. M

    Solving Stresses in a Rod: Radius Calculation

    Homework Statement In the steering arrangement below, axle 1 is a circular cross section rod. It is hold by two bearings. F1= 476 N M1 = 15 Nm Fw2 = 304.75 N, and we know that the moment imposed by Fw2 is equal to M1 l5 = 0.2 m l8 = 0.1 m The tensile yielding stress: \sigma = 235 Mpa safety...
  26. H

    Calculating Electric Field of Cylindrical Rod and Shell

    Homework Statement An infinitely long conducting cylindrical rod with a positive charge lambda per unit length is surrounded by a conducting cylindrical shell (which is also infinitely long) with a charge per unit length of -2 \lambda and radius r_1, as shown in the figure. What is E(r)...
  27. R

    Charge on a nonconducting rod with a conducting shell

    A charge of uniform linear density 2.20 nano Coulombs per meter is distributed along a long, thin, nonconducting rod. The rod is coaxial with a long conducting cylindrical shell (inner radius = .0600 m, outer radius = .104 m). The net charge on the shell is zero. a) What is the magnitude (in...
  28. S

    Calculating Angular Velocity and Time for Insect on Rotating Rod

    A rod AB having mass M ,pivoted at mid point at 0 is in horizontal..An insect having same mass M Fall vertically on rod at mid point C between 0 and B with speed V..It starts moving towards end B such that angular velocity of rod remains constant ..If the insect reached at B when rod has rotated...
  29. R

    Tapping a steel rod with a hammer-standing waves

    Homework Statement so the rod is of length l, and the speed of a transverse wave is v_w. It asks for the possible frequencies f_i. The rod is held in the centre so a node exists here.Homework Equations look below The Attempt at a SolutionI know that v_w = \lambda * f_i So it follows that i...
  30. D

    Energy required to bend an elastic rod

    Thinking in terms of the conservation of energy, it seems to make sense that if you took a relatively elastic rod with hooks on either end, so that it could be bent all the way around and made to hook to itself (and make a loop), that the energy required to bend it into a closed loop would be...
  31. I

    Finding the magnitude of the eletric field of a uniformly charged rod.

    Homework Statement "A rod of 13.1 cm long is uniformly charged and has a total charge of -23.2 micro coulombs. Determine the magnitude of the electric field along the axis of the rod at a point 52.1575 cm from the center of the rod. The Coulomb constant is 8.98755e9 N M^2/C^2. Answer in units...
  32. R

    Charged rod in your hand stays charged

    Homework Statement When you rub a rubber rod with fur it becomes negatively charged. How does it keep it's charge if it's in your hand? Homework Equations The Attempt at a Solution We did this in the lab and it definitely stays charged (at least long enough to observe some...
  33. N

    Charge and excess electrons in a rod

    Homework Statement A charged nonconducting rod, with a length of 3.00 m and a cross-sectional area of 5.37 cm2, lies along the positive side of an x-axis with one end at the origin. The volume charge density ρ is charge per unit volume in coulombs per cubic meter. How many excess electrons...
  34. C

    Transverse vibration in a solid metal rod

    I roughly understand that when we hit a metal rod right into the end will excite longitudinal vibration in the metal rod, and the place we hold will be a node. the position i hold will kind of determine the frequecy of the ringing sound produced. Is that right? But what will happen if we hit...
  35. G

    Self-torque of a compressed rod?

    Two charges, q1=q2=q>0, are held apart by a dielectric rod of length L. Everything is at rest in the xy-plane of IRF K, with x1=y1=0 and x2=L cos(theta), y2=L sin(theta), 0<theta<pi/2. Viewed from frame K’, moving in the positive x-direction of K at speed v, the Lorentz forces on the two...
  36. F

    Finding Electric Field on the Bisector of a Non-Uniformly Charged Rod

    This question has been giving my brain some trouble. I think i have the Electric Field integral calculated correctly (but I'll post that up here too just in case I'm wrong which is likely) but when I get down to finding the charge on the rod I literally am making a wild guess at the solution...
  37. S

    Self-Induced Magnetic Field in a moving rod with current

    Hi, In my book, they use an example to explain motional emf. The example consists of a rectangular circuit with a resistor on the left side and a moving bar on the right side. There already exists a magnetic field pointing into the paper and the bar is given an initial velocity to the...
  38. S

    Angular Momentum of a uniform rod

    A uniform rod of length L rests on a frictionless horizontal surface. The rod pivots about a fixed frictionless axis at one end. The rod is initially at rest. A bullet traveling parallel to the horizontal surface and perpendicular to the rod with speed v strikes the rod at its center and becomes...
  39. A

    What force is the pin exerting on the rod?

    A thin rod of uniform mass M and length L is attached to a string at one end to the ceiling and a pin at the other end to the wall. The rope (connecting the ceiling and the horizontal rod) is cut at t = 0 s. 1) What is the force of the pin at t = 0 seconds? 2) When the rod swings...
  40. G

    Nonconducting Rod: How to Determine Electric Potential at x=L+d?

    Homework Statement There is a nonconducting rod of negligible thickness located along the x axis; its ends have coordinates x = 0 and x = L. It has a positive, nonuniform, linear charge density (lambda) = (alpha)x; alpha is constant. An infinite distance away, th eelectric potential is zero...
  41. N

    Collision with a pinned and unpinned rod on a frictionless surface

    1. The Problem: (Collision with a thin rod -- pinned and unpinned) A small object with mass n and an initial velocity of v sticks to a long thin rod of mass m and length l. The motion takes place on a horizontal frictionless surface. Answer the questions for the situation where a) the rod...
  42. C

    Angular velocity of a Rod after a Ball hits it.

    Homework Statement A horizontal bar of mass 3.0 kg and length 1.0 m is free to rotate about a vertical axis through its center. A clay blob of mass 1.0 kg traveling at a velocity of 2.0 m/s in the direction shown collides with the end of the bar and sticks to it. Find the magnitude of the...
  43. D

    Calculate the tension in the rod

    Homework Statement A steel rod 4.00 cm in diameter is heated so that its temperature increases by 70.0 C. it is then fastened between tow rigid supports. The rod is allowed to cool to its original temperature. Assuming that Young's modulus for the steel is 20.6 * 10^10 N/m^2 and that its...
  44. K

    Calculating Torque to Turn a Rod

    I am working on a senior design project, and we need to calculae the torque needed by a DC motor to turn a threader rod. Any ideas as to how to calculate the torque needed to turn a rod? .75" Diam., 1ft length, will be lifted/lowered up and down at 90° to level ground. I know I'm new, but any...
  45. S

    Solve Rotational Friction Problem with Steel Rod & Balls

    Homework Statement Attached to each end of a thin steel rod of length 1.00 m and mass 6.80 kg is a small ball of mass 1.15 kg. The rod is constrained to rotate in a horizontal plane about a vertical axis through its midpoint. At a certain instant, it is rotating at 43.0 rev/s. Because of...
  46. J

    What percentage of the total mass of the pendulum is in the uniform thin rod?

    Homework Statement Christy has a grandfather clock with a pendulum that is 1.070 m long. (a) If the pendulum is modeled as a simple pendulum, what would be the period? Already solved (b) Christy observes the actual period of the clock, and finds that it is 1.20% faster than that for a...
  47. fluidistic

    What is the function for temperature distribution in a rod with heat springs?

    Homework Statement A rod with length L and section A has its extremities in contact with 2 springs of heat whose temperatures are T_A and T_B such that T_A>T_B. The rod is an environment where the temperature is worth T_0 (constantly). a)Determine the function T(x) that describes the...
  48. I

    Classical mechanics-acc. of a rod using inertia

    1. Homework Statement two people are holding the ends of a rod length l and mass M, show that if one person let's go the initial acceleration of the free end is 3g/2 3. The Attempt at a Solution i worked out the moment of inertia about centre mass (cm) and got = Ml2/12 because L=Iw...
  49. I

    Classical mechanics-acc. of a rod using inertia

    Homework Statement two people are holding the ends of a rod length l and mass M, show that if one person let's go the initial acceleration of the free end is 3g/2 The Attempt at a Solution i worked out the moment of inertia about centre mass (cm) and got = Ml2/12 because L=Iw...
  50. T

    What are the Stress and Strain in each rod?

    Homework Statement A copper rod of 2 meters is joined to a steel rod with length (ls) and with cross sectional area of 1.0cm2 and 2.0cm2 respectively the compound rod is subjected to an equal and opposite force of 3x104N. Find: a) The length of the steel rod if the elongation of the steel...
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