What is Tension in string: Definition and 43 Discussions

In physics, tension is described as the pulling force transmitted axially by the means of a string, a cable, chain, or similar object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression.
At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length.
In physics, tension, as a transmitted force, as an action-reaction pair of forces, or as a restoring force, may be a force and has the units of force measured in newtons (or sometimes pounds-force). The ends of a string or other object transmitting tension will exert forces on the objects to which the string or rod is connected, in the direction of the string at the point of attachment. These forces due to tension are also called "passive forces". There are two basic possibilities for systems of objects held by strings: either acceleration is zero and the system is therefore in equilibrium, or there is acceleration, and therefore a net force is present in the system.

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  1. A

    What causes knots and stress when untwisting ropes?

    [Mentor Note -- thread moved from the schoolwork forums to GD as it seems like a more general question] Homework Statement:: Topoisomerases help in relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix (Topoisomerases are enzymes that...
  2. A

    Tension in string pulling two carts

    F - T = m*a 820t - T = m*0.7805t T = 820t - m*0.7805t I am confused what I would use as mass? Mass of cart A, or mass of cart A and tractor?
  3. E

    Effect of temperature on vibrational frequency of a violin string

    Variables: Dependent: Vibrational frequency of violin string (Measured using mobile tuning app) Independent: Temperature in which string is plucked (Measured using infrared thermometer) Controlled: Violin String, Tension of violin string, Length of violin string, Method of plucking...
  4. Asterast

    Tension in the string while it descends

    so I took string below point A and Block as a system. Taking mass of string below point A as m and mass of block M. Taking downward direction as X axis. I get Mg+mg-T, Taking T as tension by upward part of string. Now the question says about block descending with acceleration a. so again forces...
  5. prakhargupta3301

    What is the tension in string?

    Homework Statement We have to find T1 and T2 From right to left objects are: A B C Homework Equations F=ma The Attempt at a Solution Okay. So I found acceleration of whole system: F=ma 200N= (20+10+5)*a 200/35=a a= 40/7 ms-2 Now, finding T1 is fairly simple: f=ma T1=5*(40/7) T1=200/7 Newtons...
  6. V

    Vector addition and the force applied to the shaft of the pulley

    Homework Statement Hello, I am currently studying mathematics and physics on my own, and I ran into a type of problem in physics that is a bit unclear to me. Say we have pulley at the top of an inclined plane with a base angle of alpha and the top angle is alpha. Homework Equations I assume...
  7. C

    Tension in 4 strings suspending object at 4 different points

    Homework Statement A grid made of ropes is suspended by its four corners with strings tied to four different points on a building. Three of which are fixed and fourth is attached to a pulley which is in turn fixed to the building. Given data : Grid mass is 25 kilogram suspended at a height of...
  8. H

    3 masses and an inclined pulley system

    Homework Statement The tension between the 6 kg and 4 kg object as=2.1m/s Fnet = 40N assume 0.4 kinetic friction coefficent Homework Equations T1- Fnet = mas The Attempt at a Solution acceleration is negative because the object is decelerating as it goes up the slope so T1-40N = 6(-2.1) T1 =...
  9. R

    Tension in string when ball is at the top of a circle

    Homework Statement A child is swinging a .325 kg ball at the end of a .74 m long string in a vertical circle. string can withstand a tension of 12 N before breaking. What is the tension in the string when the ball is at the top of the circle if its speed at that point is 3.4 m/s? Homework...
  10. MickeyBlue

    Tension in two wires at unknown angles

    Homework Statement An object at rest is suspended from two strings (A and B) as shown in the diagram, with A shorter than B. The object pulls on the point O with a force of 20 N. Each of the strings also exerts a force on the Point O. The angle between the strings at O is 90o. Which of the...
  11. Nicholaz99

    Tension in string for a bob pendulum

    Homework Statement ------------------------------------- |.\ |...\ |...\ |...\ Q...O P O=the bob Teta=60 degree The bob of a simple pendulum is released from rest at P. The mass of the bob is m and...
  12. L

    Tension in string at a point on a frame

    Homework Statement Hi all. What concerns me here is that it's worth 10 marks, but the solution I've tried only takes 2 steps. Am I missing some relation between the frame support and the pulley altering the components of the tension, or is the solution really just a basic trig conversion...
  13. DanielleG

    Centripetal Force Theory Questions

    Homework Statement Answer True, False, or Cannot tell to each of the five statements below. A small projectile is launched horizontally 1 m above the surface of a smooth, airless planet, with sufficient speed for orbit. A bug riding in a small hole in the projectile has apparent weight...
  14. G

    Finding tension in string in vertical circle

    Homework Statement [/B] Your niece finds her father's watch. The light watch chain has a length of 48 cm, and the mass of the watch is 270 g. Your niece swings the watch in a vertical circle, maintaining the speed of the watch at 2.3 m/s. Find the tension in the chain when it makes an angle of...
  15. O

    50N from left, 50N from right. Tension in string still 50N?

    Let's say I go to the store and purchase a rope. On the package of string, it says that the string can only withstand 100 Newtons before the rope snaps. I go home and test the tension in the rope. I tell a friend to pull on the rope at 99 Newtons while I pull on the rope with 99 Newtons. Did...
  16. gasar8

    Tension in string and oscillation

    We've got a 0,5m string attached to a frame and has its own fundamental frequency at 440Hz. We cool our system for 15°C. What is the proper frequency now? String length l=0,5m String section S=0,02 mm^2 String density ρ=7800 kg/m^3 Young module E=2*10^5 N/mm^2 Fundamental frequency ν=440Hz ΔT=...
  17. J

    Tension in string in system with multiple objects?

    Homework Statement I am stuck on this problem: So the question is asking for F21, F12, F32, and F23. (That's the force by 2 on 1). The mass of m2 is variable. There are four cases where I need to solve for the forces: when m2 has mass of 3kg, 0.3kg, 0.03kg, and 0kg. The mass of m1 = 2.5kg, the...
  18. arpon

    Tension in String Homework: 300g Disk at 10ms^2

    Homework Statement [/B] A string is wound around a uniform disk of radius ##10cm## and mass ##300g##. The disk is released from rest when the string is vertical and its top end is tied to a fixed bar. Determine the tension in the string. [ ##g = 10 ms^{-2} ##] Homework EquationsThe Attempt at a...
  19. F

    Tension in String between two blocks

    Homework Statement Block 1, of mass m_1 =2.6kg and block 2 of mass m_2=1.4kg are connected by a massless string. Block 2 then experiences a force F=18N acting in the postivive x direction and at an angle of \theta = 38° . The coefficiant of kinetic friction between the floor and both of the...
  20. S

    Force - finding tension in string

    Homework Statement A fuzzy-dicer makes an angle of θ = 49.6° with respect to the vertical. The mass of the fuzzy dice is 1.0 kg. What is the tension? 2. The attempt at a solution (deleted answer)
  21. V

    Find Tension in String Connecting Two Charged Spheres

    Two charged objects of charge q. Coulomb's law states that the force on one sphere by the field of the other is: F = qE But each sphere experiences that, correct? So the tension for the string would be 2F. Is that correct?
  22. tony873004

    Tension in string - hanging block

    Homework Statement Find the tension in string 1 I don't get the same answer as the solution manual. My attempt: The y-component of string 2’s tension must equal the weight of the block. The x-component of string 2’s tension must equal the tension of string 1. T1=T2x=T2y/tanθ =23°...
  23. V

    Finding Tension in String Connected to Electrically Repelled Sphere

    Homework Statement Two uniformly charged spheres are suspended by strings of length L from vertically adjustable supports. The spheres are in static equilibrium. The angles with respect to the vertical are Q=14.9°, and T=20.7°. The tension in the string supporting sphere Z (Z with respect to...
  24. M

    Tension in string of objects connected question :o

    Homework Statement In the attachment! This is a multiple choice question where you have to choose one of the strings. Intuitively I chose Z as I would think that in the first fraction of time it would feel the force acting on it first. However, if this wasn't a multiple choice I...
  25. J

    Calculate Tension in 5m String Attached to 4kg Bob

    Homework Statement Calculate the tension in a 5 m string attached to a 4 kg bob that is moving in horizontal circles of 0.6 m radius. Homework Equations The Attempt at a Solution α= tan-1 0.6/5 = 7 degree T cos α = m*g T= m*g/cosα T=4*9.8/0.12 T=326.6 N I...
  26. D

    Caluclating tension in string that is moving in horizontal circles.

    Hi all, First of all I'd like to say thank you to you all for providing a great forum which has been a great help to me working through my ics home learning course. As i have learned on here and other places on the internet the information I have in my course materials is not always...
  27. P

    Tension in string, vertical plane

    Homework Statement Keys with a combined mass of 0.100 kg are attached to a 0.25 m long string and swung in a circle in the vertical plane. What is the tension in the string at the bottom of the circle? Known: Mass = 0.100 kg Radius = 0.25 m Homework Equations Fc = mv^2/r...
  28. U

    What is the tension on a string wrapped around a pulley?

    Homework Statement [PLAIN]http://nicholascrumrine.net/otherpics/physics/HW4_6.jpg Homework Equations Sum(F)=MA w=v/r The Attempt at a Solution My assumptions are as follows: The sum of the tensions on the left side of the pulley is equal to the tension in right side of the...
  29. C

    How Is Tension Calculated in a Pendulum String at 45 Degrees?

    The mass of the ball is m, as given below in kg. It is released from rest. What is the tension in the string (in N) when the ball has fallen through 45o as shown. Hint: First find the velocity in terms of L and then apply Newton's 2nd law in normal and tangential directions. If you do it...
  30. J

    Tension in string of object suspended in liquid

    Homework Statement an aluminum object with volume 100 cm^3 and density 2700 kg/m^3 is suspended in ethyl alcohol (density 790) by a string. what's the tension in the string? Homework Equations Fy = Fb + T - mg T = mg - Fb Fb = p_f * v_f * g = p_o * v_o * g The Attempt at a...
  31. I

    Finding Tension in Suspended Spheres with Given Mass and String Length

    This isn't really homework, just doing some revision. Homework Statement Find the tension in each string. Two spheres both of mass, m = 15kg. Diameter of each is 25cm. Each string 35cm long. Spheres are suspended on strings with other end attached to same point on ceiling. Therefore spheres...
  32. V

    Tension in string when force is applied to both ends

    Hi, I've got a quick question about tension. If there is a force applied to both ends, the total tension is the sum of those forces, right (i.e., they don't cancel each other out)? TIA!
  33. S

    Tension in string with rollers

    I have read at many places that tension in the string remains same throught the string. I have a string which is held tight at two ends. It is passing around different rollers. Now, I have small weight hanging on the string at one place. Does this mean that I have same tension throught the...
  34. S

    Circular Motion, a swinging ball and tension in string

    http://www.mech.uq.edu.au/courses/mech2210/yat/q/swinging_ball.jpg The mass of the ball is m, as given below in kg. It is released from rest. What is the tension in the string (in N) when the ball has fallen through 45o as shown. m[kg] = 3.335 I've used the formulae: v = sqrt[2gL(sin...
  35. J

    Is the Calculated Tension in the Upper String Correct for a Stationary Ball?

    I have a ball. It is attached to a wall by a horizontal string to the left. it is attached to the ceiling by another string at an angle theta from the vertical to the right. The ball is not moving. So I worked out that the tension in the upper string is w/(cos theta) , where w is weight. Is...
  36. P

    Website title: Understanding Tension and Energy in a Vertical Swing

    A rock of mass 200g is attached to a 0.75m long string and swung in a vertical plane. A) what is the speed that the rock must travel so that its weight at the top of the swing is 0? B) what is the tension in teh string at the bottom of the swing? C) if the rock is now moved to a horizontal...
  37. H

    Tension in String A after B Cut

    In the attachment given below what will be the tension in string 'A' immediately after the string 'B' is cut. Assume all that the situtation requires.
  38. K

    What is the ratio between tensions in different positions for a swinging ball?

    Hi, Can someone please explain how to do this problem? I really don't understand. A ball is held at rest in position A as shown in the figure by 2 light cords. The horizontal cord is cut and the ball swings as a pendulum. What is the ratio of the tensions in the supporting cord, in position...
  39. A

    Find Tension in String when Yo-Yo is Released

    Let's say you have a yo-yo that is constructed from two circular masses connected by a small hub. If the radius of the hub is r and the radius of the circular masses is R, how can I find the tension in the string when the yo-yo is released? Assume each circular mass has mass M and the hub is...
  40. D

    Tension in String of 5.5kg Object in Accelerating Elevator

    A 5.5-kg object is suspended by a string from the ceiling of an elevator that is accelerating downward at a rate of 2.5 m/s^2 What is the tension in the string?
  41. F

    Tension in string attached to two fixed points

    I'm having trouble with this physics problem: A piece of steel wire (diameter 2mm) is connected between two fixed points. The tension in the wire is 120N at 0 degrees Celcius. At what temperature is the tension 0? I assume that I first have to calculate how much "too short" the string is...
  42. D

    Problem proving tension in string

    Ok so i have a homework problem again :) This time it's a simple pendulum swing and the question is as follows: "Prove that the tension in the string of a simple pendulum when the string makes an angle \theta with the vertical is approximately mg(1 + \theta^2_0 - (3/2)\theta^2 where m is the...
  43. U

    Tension in String One of 5 kg Mass at 45 Degree Angle

    Two strings are attached to a 5 kg mass. String one is at a 45 degree angle and the other is horizontal. What is the tension in string one?