What is Spring balance: Definition and 16 Discussions

A spring scale or spring balance or newton meter is a type of mechanical force gauge or weighing scale. It consists of a spring fixed at one end with a hook to attach an object at the other. It works by Hooke's Law, which states that the force needed to extend a spring is proportional to the distance that spring is extended from its rest position. Therefore, the scale markings on the spring balance are equally spaced.
A spring balance can be calibrated for the accurate measurement of mass in the location in which they are used, but many spring balances are marked right on their face "Not Legal for Trade" or words of similar import due to the approximate nature of the theory used to mark the scale. Also, the spring in the scale can permanently stretch with repeated use.
A spring scale will only read correctly in a frame of reference where the acceleration in the spring axis is constant (such as on earth, where the acceleration is due to gravity). This can be shown by taking a spring scale into an elevator, where the weight measured will change as the elevator moves up and down changing velocities.
If two or more spring balances are hung one below the other in series, each of the scales will read approximately the same, the full weight of the body hung on the lower scale. The scale on top would read slightly heavier due to also supporting the weight of the lower scale itself.
Spring balances come in different sizes. Generally, small scales that measure newtons will have a less firm spring (one with a smaller spring constant) than larger ones that measure tens, hundreds or thousands of newtons or even more depending on the scale of newtons used. The largest spring scale ranged in measurement from 5000–8000 newtons.
A spring balance may be labeled in both units of force (poundals, Newtons) and mass (pounds, kilograms/grams). Strictly speaking, only the force values are correctly labeled. In order to infer that the labeled mass values are correct, an object must be hung from the spring balance at rest in an inertial reference frame, interacting with no other objects but the scale itself.

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  1. tellmesomething

    Help again in interpreting a pulley with a spring and a block

    I guess im still a bit rusty with spring problems. Heres the given figure: Can someone walk me through what exactly would happen when the system is released from rest. Mainly im concerned about the 5kg block when it moves down by say a distance x, this means the gravitational force is more...
  2. cianfa72

    I Spring balance analysis from a system point of view

    Hi, I was thinking about a simple scenario in the framework of Newton (classic) mechanics. Take a spring scale/balance fixed at one end (wall) with a body attached to the other end's hook. From an analysis point of view we can consider as "system" the spring scale + the wall + the body. Then...
  3. rudransh verma

    Pulley and weights hanging from spring balance

    Net force acting downwards is ##5g-g=4g## in downward direction. Net force on pulley is ##2T-4g##. Weight measured by balance?
  4. cwill53

    How can I solve the Spring Balance problem using alternative methods?

    Here is the diagram: I’ve only drawn the diagram and made equations for the sum of forces in the x-directions and y-directions: ##\sum F_{x}=(7 lbs)sin\beta+(8 lbs)sin\alpha=0## ##\sum F_{y}=(8 lbs)cos\alpha+(7 lbs)cos\beta-13 lbs=0##
  5. Suyash Singh

    What is the formula for calculating force using a spring balance?

    Homework Statement Homework Equations only basic school level physics will be needed in this question. The Attempt at a Solution The mass m1 pulls spring from first side and m2 pulls spring from the other side therefore reading should be m1-m2. But my answer is wrong. I can't understand what...
  6. Mateus Buarque

    Simple Harmonic Motion and equilibrium of springs

    The figure below shows a system in equillibrium. The pulley and the springs (both with constants "k") are ideal. The period of oscillation of the mass A is given by: Relevant equations: F = -kx (SHM) I tried to do a "force diagram" and set up some geometric relations but it´s not working.
  7. T

    What is the efficiency of an accelerometer?

    I 've got a project, and I 've been searching all over to find an answer; what is the efficiency of the accelerometer itself (p.e. in its use in smart-devices as screen-orientation method)? Or do you know, what is the efficiency (approximately of a regular spring (NOT into void)? Thank you...
  8. M

    Finding the effect of air resistance on period of oscilation

    Homework Statement I'm currently working on the "cavendish" experiment and wish to use/develop a method separate from the casus we've been provided. Now I've nicely calculated and derived everything I need to know, including all the corrections that have to be made for the mass of the rod, the...
  9. L

    Pulley + spring balance problem.

    Homework Statement A light spring passing over a smooth pulley carries a spring balance of mass 1 kg and two weights of masses 1 kg and 2 kg. the reading on the balance will be Homework Equations 3. The Attempt at a Solution [/B] to my knowledge whatever the tension above the spring balance...
  10. T

    MHB Solving the Spring Balance Problem: Work Done Stretching 5.0-12.2in

    Hi all, I could use some assistance with the following problem. "The spring of a spring balance is 5.0in. long when there is no weight on the balance, and it is 9.6in. long with 8.0 lb hung from the balance. How much work is done stretching it from 5.0in to 12.2in?" So far, I know to take...
  11. R

    How to use a spring balance in space?

    A spring balance cannot be used to measure the weight of anything under the conditions of a space shuttle. Is there any way you might use a spring balance to compare the 'heaviness' of twin babies born on the shuttle? Discuss. I don't know how you'd use a spring balance in the shuttle.. Any...
  12. P

    Spring Balance: Mass or Weight? Clearing Out Confusion

    By definition, the difference between Mass and Weight is easy to comprehend. However, I am really confused, confused to the level I feel like ripping all the hair out of my head, with spring balances: After researching a lot, I think that as I step on a spring balance the spring will extend...
  13. S

    Understanding Spring Balances and Series Setups

    Homework Statement This was a concept question my lecturer gave us, and although he tried to explain it thoroughly, I still didn't get it. So I was hoping someone could help me out. There are 2 parts to this question Firstly a spring balance is attached hanging from a celling using a...
  14. S

    Question on oscillations spring balance and fish

    The scale of a spring balance reading from zero to 180 N is 7.00 cm long. A fish suspended from the balance is observed to oscillate vertically at 2.50 Hz. What is the mass of the fish? Neglect the mass of the spring. ________ kg Attempt k =(180-0)/(7-0) = 25.714 N/m frequency =...
  15. L

    How Does a Spring Balance Measure Force in Different Elevator Scenarios?

    ok so i am completely lost on all this force stuff...help...please An object is hung from a spring balance attached to the ceiling of an elevator cab. The balance reads 65 N when the elevator is standing still. (a) What is the reading when the elevator is moving upward with a constant...
  16. D

    Finding spring balance readings (Newtons)

    Homework Statement Find the readings on each of the balances in these 4 situations (strings are massless and incline is frictionless): (sorry about the photo - don't know how to fix it) Homework Equations F=ma, W=mg The Attempt at a Solution 1) Seems easy enough. I am...