What is Bead: Definition and 133 Discussions

A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood or pearl and with a small hole for threading or stringing. Beads range in size from under 1 millimetre (0.039 in) to over 1 centimetre (0.39 in) in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork is the art or craft of making things with beads. Beads can be woven together with specialized thread, strung onto thread or soft, flexible wire, or adhered to a surface (e.g. fabric, clay).

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  1. S

    Charge on a glass bead derived from potential difference between 2 points

    Homework Statement A 2.0 mm diameter glass bead is positively charged. The potential difference between a point 2.0 mm from the bead and a point 4.0 mm from the bead is 500V. What is the charge on the bead? Actual Answer 4.2*10^-10 I am unable to understand or even get near this...
  2. R

    How fast is this bead traveling down the wire

    A big metal bead slides due to gravity along an upright frictiion-free wire. It starts from rest at the top of the wire as shown in the sketch. How fast is it traveling as it passes. http://https://www.physicsforums.com/attachment.php?attachmentid=22509&stc=1&d=1260854052 Point B? Point...
  3. O

    Uniform Circular Motion; bead on a string.

    1. Homework Statement An 100g bead is free to slide along an 80cm long piece of string ABC. The ends of the string are attached to a vertical pole at A and C, which are 40cm apart. When the pole is rotated, AB becomes horizontal. a) find the tension in the string b) find the speed of the...
  4. L

    A bead on a spinning rod with magnetic field

    Homework Statement A bead of mass m and charge q is placed on a frictionless, rigid rod that is spun about at one end at a constant rate w on the xy plane. There is a constant magnetic field in space B = B_0\hat{z} Homework Equations Write the Lagrangian for the system, use the generalized...
  5. T

    Gravitational potential energy bead of mass

    Homework Statement A bead of mass m slides without friction on a smooth rod along the x-axis. The rod is equidistant between two spheres of mass M. The spheres are located at x=0 , y= \pm a. a. Find the potential energy of the bead. b. The bead is released at x = 3a with an initial...
  6. M

    Rotating steel wire with bead on it

    Homework Statement A small bead with a mass of 100 g slides without friction along a rotating semicircular steel wire, where the semicircle has radius 10cm. The steel wire rotates about a vertical axis at a rate of 2 revolutions per second. Find the positions at which the bead will be...
  7. J

    Find the period of oscillation of a bead on a cycloid string

    Homework Statement Find the period of oscillation of a bead on a cycloid string. If it matters, the original equations of the cycloid were x=a(\theta-sin\theta) and y=a(1+cos\theta) Homework Equations This is a small part of a larger problem... I found the equation of motion of a bead on a...
  8. F

    Charge of bead falling through an electric field

    Homework Statement postively charged bead having a mass of .61g falls from rest in a vacuum from a height of 5.9 m in a uniform vertical electric field of magnitude 11600 N/C. The bead hits the ground at a speed of 19 m/s. acceleration of gravity is 9.8 m/s^2. find the charge on the bead...
  9. R

    Exploring Circular Motion: A Bead on a Ring

    Circular Motion! Homework Statement A bead of mass m moves on a smooth circular ring of radius a which is fixed in a vertical plane. Its speed at A, the highest point of its path, is v and its speed at B, the lowest part of its path, is 7v. a) show that v= [square root](ag/12) b) find...
  10. R

    Finding the Electric Field Needed to Suspend a Charged Bead

    1. Homework Statement A 5.0×10^−2g plastic bead is charged by the addition of 1.0×10^10 excess electrons. What electric field (strength) will cause the bead to hang suspended in the air? 2. Homework Equations 3. The Attempt at a Solution It has something to do with F = Eq but i...
  11. W

    Another Lagrangian question: Bead sliding along a horizontalotating ring

    Another Lagrangian problem: Bead sliding along a horizontal rotating ring Homework Statement A horizontal ring of mass M and radius a rotates freely about a vertical axis passing through a point on its circumference. If a bead of mass m slides along the ring without friction, what is the...
  12. W

    Lagrangian mechanics: Kinetic energy of a bead sliding along a bent wire

    Homework Statement Determine the kinetic energy of a bead of mass m which slides along a frictionless wire bent in the shape of a parabola of equation y = x2. The wire rotates at a constant angular velocity \omega about the y-axis. Homework Equations T = \frac{1}{2}m(\dot{x}^2 +...
  13. G

    The Classical Bead Problem (Volumes of Sphere and Cylinder)

    Hello. I'm having trouble with the following problem. A round hole is drilled through the center of a spherical solid of radius r. The resulting cylindrical hole has height 4 cm. What is the volume of the solid that remains? Here's the pic that I drew, I hope it's useful...
  14. D

    Frictionless Bead Sliding Down A Parabola

    Homework Statement It seems simple, doesn't it? A bead starts from (0,1/2) and simply slides down the parabola y=(1/2)(x-1)[SUP]2 under gravity. The problem is to get its position rel. to origin in terms of time, ie. r = [x(t),y(t)]. Anyone into this? Homework Equations y' = x-1 = tan...
  15. Chandra214

    Purpose of Ferrite Bead in Ground isolation

    Hi, please let me know the purpose of having a ferrite bead isolation for ground (between digital and power)? as far as i understand. the ferrites will be helpful in case of power noise filtering. And noise from digital line return path wouldn,t affect the power levels as it might do for...
  16. V

    How Does a Bead Behave on a Rotating Hoop?

    Homework Statement Consider a bead of mass m that can slide freely on a circular hoop of radius a which lies in a vertical plane. The hoop rotates about a vertical axis through its centre at fixed angular velocity \omega. The angle \theta is the polar angle of the bead measured from the...
  17. S

    How Does Bead Momentum Affect Post-Collision Movement on a Frictionless Surface?

    A 0.400 kg bead slides on a straight frictionless wire with a velocity of 3.50 cm/s to the right. The bead collides elastically with a larger 0.600 kg bead initially at rest. After the collision, the smaller bead moves to the left with a velocity of 0.70 cm/s. Find the distance the larger bead...
  18. R

    Advanced 2-D Motion Problem - Bead on Wire

    Homework Statement "Consider a bead of mass m that is free to move around a horizontal, circular ring of wire (the wire passes through a hole in the bead). You may neglect gravity in this problem (assume the experiment is being done in space, far away from anything else). The radius of the...
  19. C

    What electric field strength will cause the bead to hang suspended in the air?

    1. A 0.180g plastic bead is charged by the addition of 0.700 x 10^10 excess electrons. What electric field strength will cause the bead to hang suspended in the air? 2. Is amount of excess electrons the exact same as the charge of the bead?? 3. I am sure you use F=qE. But I am...
  20. I

    Bead confined to a circular hoop

    [SOLVED] Bead confined to a circular hoop Homework Statement A bead with mass m is confined to traveling along a cirlcular hoop with radius r. The bead can slide without friction along this hoop. The hoop, which is vertical, rotates with an angular velocity (omega). What is the angle...
  21. J

    Charge on a bead given the Electric Potential

    I currently have this problem for homework: A 1.80 -diameter glass bead is positively charged. The potential difference between a point 1.80 from the bead and a point 4.00 from the bead is 470 . What is the charge on the bead? And I cannot seam to get it. First I thought that I should...
  22. P

    Bead and loop-the-loop: normal force?

    Bead and loop-the-loop: normal force?? Homework Statement A bead sliding around a loop the loop. Given its mass and speed at the top of the loop, we want the normal force on it. Homework Equations mv^2/r = mg + N The Attempt at a Solution I have the correct solution that the...
  23. D

    Solving for Kinetic Energy at Top of Loop-the-Loop

    Homework Statement A bead slides without friction around a loop-the-loop. The bead is released at height y from the bottom of the loop, which has radius r. What is the instantaneous kinetic energy K at the top of the loop so that the bead would press the track with an upward force F=mg/2...
  24. T

    Solving Oscillations: Bead on a Block & Spring

    Homework Statement A block attached to a spring underneath oscillates vertically with a frequency of 4Hz and an amplitude of 7.00cm. A tiny bead is placed on top of the block jut as it reaches its lowest point. Assume the bead's mass is so small that its effect on the motion of the block is...
  25. mbrmbrg

    Maximizing/Minimizing Volume of a Sphere with Cylinder Drilled Through Center

    We're trying to maximize (then minimize) the volume of a sphere wuth a cylinder drilled through the center. So I have a circle with the equation x^2 + y^2 = R^2, and I'm going to rotate it around the y-axis. Actually, I'm only going to rotate the quarter of it that lies in the first quadrant...
  26. N

    Bead on a Wire and Harmonic Motion

    A wire could be shaped like a sinusoidal function and then we could say the bead moves harmonically. The shape of the wire, so that bead occilates around X = 0. Y = -50*cos(10X) If we ignore friction and give it a small dispalcement then it is possible to find angular frequency...
  27. S

    Lagrangian mechanics of a bead of mass

    consider a bead of mass m constrained to move on a fricitonless wire helix whose equations in cylindrical polar coords is z = a phi where a is some constant the bead is acted upon by a force which deends on the distance from the cneter only. Formulate the problem using s the distance along...
  28. L

    A bead in circular motion in space

    Consider a bead of mass m that is free to move on a thin, circular wire of radius r. The bead is given an initial speed v0 and there is a coefficient of kinetic friction us. The experiment is performed in a spacecraft drifting in space. Find the speed of the bead at any subsequent time t. I...
  29. R

    Label Puzzle: Determine Bead Contents

    In one container there are two black beads, in another two white beads, and in a third there are one black and one white bead. They are labelled appropriately BB, WW, and BW. Someone moved the labels in such a way that for each container the label doesn't show its contents. Can you determine the...
  30. P

    Acceleration of a bead sliding down a Helix

    Can a bead desecnd down a helix have zero vertical component for its acceleration? (i.e. If I found my result to only has coefficients for its horizontal radial component unit vector (e_r), but zero for that of the vertical unit vector (e_z) ! ... That means I got zero vertical component for...
  31. K

    How Does the Angle Affect Bead Stationarity in Rotating Circular Motion?

    A small bead with a mass of 100grams slides along a semicircular wire with a radius of 10 centimeters that rotates about a vertical axis at a rate of 2 revolutions per second.Find the value of angle p for which the bead will remain stationary with respect to rotating wire. Any idea on this?
  32. K

    DNA-Bead Attachment Protocol: Streptavidin & Biotin/DIG

    Does anybody have a good protocol for DNA - bead attachment ? The Bead is streptavidin coated and the DNA has biotin and DIG on its ends.
  33. T

    Optics: Glass Bead & Center of Curvature

    Let's say we have an objet O in front on a glass bead. The first surface will be a convex surface, hence the centre of curvature is in the back of the surface, which gives +R_1. The object, is a real object in front of the surface, which makes it +p_1, however for the second refraction, we take...
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