What is Strength: Definition and 1000 Discussions

Compressive strength or compression strength is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to Tensile strength which withstands loads tending to elongate. In other words, compressive strength resists being pushed together, whereas tensile strength resists tension (being pulled apart). In the study of strength of materials, tensile strength, compressive strength, and shear strength can be analyzed independently.
Some materials fracture at their compressive strength limit; others deform irreversibly, so a given amount of deformation may be considered as the limit for compressive load. Compressive strength is a key value for design of structures.
Compressive strength is often measured on a universal testing machine. Measurements of compressive strength are affected by the specific test method and conditions of measurement. Compressive strengths are usually reported in relationship to a specific technical standard.

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  1. B

    What is the net electric field at point P in this physics problem?

    Physics Problem , please help I'm writing a test tomorrow and want to know if I'm right. The Question : Two point charges Q1 and Q2 are spaced 3m apart. Q1's charge = 14C Q2's charge = +20 C *Q1 -------(3meters)------- *Q2 ----(2meters)---- *P Calculate the net electric field at...
  2. H

    Relationship between gravitational field strength and potential

    Hi, I am a bit confused with the relationship between gravitational field strength and gravitational potential. As far as I know, gravitational field strength is defined as: g=\frac{F}{m}=\frac{GM}{R^{2}} and gravitational potential is defined as: V=\frac{-GM}{R} Now if I...
  3. M

    MATLAB Guidance for strength of materials in matlab.

    Hi, all I have to do a project but I need some guidance. I have to make MATLAB draw bending moment and shear force diagrams of a beam which have to be loaded with a distributed load, a single force, and a single moment. First I have to make MATLAB draw a beam like in the picture.
  4. S

    How to understand the negative two-photon transition strength

    Dear all, I have calculated the rotationally averaged two-photon transition strength (DeltaTPA) using the CCSD response approach. Degenerate TPAs of ten excited states have been calculated. For most of the excited states considered, I got the positive DeltaTPAs, while for some excited states...
  5. D

    Calculating how magnetic field strength decreases with distance

    Hi everyone, I am trying to calculate the decrease in magnetic field strength over distance, using a formula I found on this thread https://www.physicsforums.com/showthread.php?t=522223 The formula given was 1/r^3, where r is the distance from the source. The same thread says the formula...
  6. T

    Ampere's Law - Magnetic Field Strength

    Homework Statement Use Ampere's Law to show that the magnetic fi eld strength at a distance R from a long, straight wire, carrying a current I, is: H = I/2\piR Homework Equations F=qVB B=\mu0I/2\piR The Attempt at a Solution I'm not sure how to answer this question. I got the...
  7. Q

    Electric field strength goes to 0

    Homework Statement Two point charges lie on the x-axis. Charge Q1= +7 μC is located at x = 0 and charge Q2 = -18μC is located at x = 25 cm. Find the point on the x-axis (in cm) where the net electric field is zero. Homework Equations E = F/C F = k(q1)(q2)/r^2 The Attempt at a Solution Okay...
  8. I

    Magnetic Field Strength versus Coil Density

    Homework Statement We did a lab where we measured the magnetic field strength of a wire coil versus the coil density of the wire coil, keeping current constant. We determined the relationship of B (magnetic field strength) versus n (coil density) to be direct. I need to explain why this is...
  9. L

    Simple electric field strength problem

    Homework Statement How far away from a 360μC charged particle is the electric field strength 49mN/C? Homework Equations E=(8.99x10^{9} x \frac{Q}{r^{2}} The Attempt at a Solution I assumed it would be a simple case of rearranging the equation to give r=\sqrt{\frac{8.99x10^{9}xQ}{E}}...
  10. T

    Calc Forces in Members FG, GD & CD: Virtual Work

    1. Calculate the forces in the members FG, GD, and CD of the truss shown in the figure by using the principle of virtual work. All horizontal and vertical members are 1m long 2. I have attached the diagram 3. I can easily calculate this using normal principles, but not understanding how to use...
  11. Q

    What factors determine the strength of a covalent bond

    I want to know what factors influence the bond enthalpy of a covalent bond and how do those factors influence the bond strength.
  12. C

    The magnetic field strength required to oscillate an electron

    Homework Statement "An electron is accelerated by a potential difference of 1 V and is injected into vacuum. How strong should the magnetic field in a vacuum be if you want the electron to circle along a loop with a radius of 10^-1m? Please indicate the direction of the magnetic field"...
  13. E

    How Do You Calculate Yield Stress in an Aluminium Single Crystal Alloy?

    Hey, this was the question could someone please help? "An aluminium single crystal alloy aircraft component is oriented such that a tensile stress is applied along a [102] direction. If slip in this material occurs on a (111) plane and in a [101] direction, compute the yield stress at which...
  14. S

    Brushed motor solid magnet strength

    hi guys! i was wondering if the solid magnet part of a brushed dc motor needs to be strong in order to make a strong motor? I'm designing a motor from scratch and wondering if i should use an existing ferrite magnet that is somewhat strong or should I design a electromagnet that is stronger...
  15. N

    Electric field strength at the center of semicircle

    Homework Statement A uniformly charged insulating rod of length 12.0 cm is bent into the shape of a semicircle as shown in the figure below. The rod has a total charge of −7.50 µC. Find the magnitude of the electric field at O, the centre of the semicircle. Homework Equations E = 2kq /...
  16. N

    Electric Field strength between 3 charges and directions

    Homework Statement Three point charges lie along a straight line as shown in the figure below, where q1 = 6.36 µC, q2 = 1.57 µC and q3 = −1.82 µC. The separation distances are d1 = 3.00 cm and d2 = 2.00 cm. Calculate the magnitude and direction of the net electric force on each of the...
  17. N

    Electric field strength of 4 charges positioned in a square shape

    Homework Statement Four charged particles are at the corners of a square of side a as shown in the figure below. (Let A = 3, B = 5 and C = 6.) (a) Determine the electric field at the location of charge q. (Use the following as necessary: q, a, and ke.) (b) Determine the total...
  18. S

    Calculating Ultimate Tensile Strength?

    Homework Statement A metal of cross-sectional area 3.22E-4 m2 is being tested in compression. At an engineering strain of 20%, the compression load of the sample is determined to be 25000lb. Calculate the true stress and true strain at that point. Assume sigma=A(epsilon)N where the strain...
  19. D

    How to predict a magnet's field strength?

    Hi, I am interested in making my own (weak) magnets exposing some ferrous metal to the magnetic field of an electromagnet, but this is theoretical rather than something I am able to actually do right now. I am wondering if there are any formulas that can help calculate/estimate the resulting...
  20. M

    Three layers of a capacitor - Voltage divider + field strength.

    Homework Statement In a plate capacitor, the plates has a area of ##100cm^2## and a distance of 3mm. The insulation between the plates is a 1mm glass plate (εr = 10), a 0.5mm thick mica plate (εr = 5) and the rest is air. The insulation layers is parallel with the capacitor plates. The...
  21. M

    Calculating Field Strength in a Plate Capacitor

    Homework Statement The insulation in a plate capacitor consists of two layers with the thickness of 1 and 2 mm, and a relative permittivity of 4 and 6. Calculate the field strength in the thinnest layer when the capacitor is connected to a voltage of 5000v. Homework Equations The...
  22. E

    Compression strength measurement

    Hello all, I have to measure the compression strength of a porous ceramic body (d=L=10 mm) using advanced force gauge, mecmesin and don't have any experience with it. The simple procedure, which I followed, was to measure the force at which the sample started to break, divided by the cross...
  23. L

    Electric Field Strength Between Two Parallel Plates Problem

    Homework Statement If the electric field strength between two parallel plates 1cm apart is 3.1kN/C, how much energy will be used by the electric field to move an electron (placed half way between the plates) 3mm nearer to the positively charged plate? Homework Equations Work Done =...
  24. W

    Could i use electromagnets to increase the strength of a high speed

    Flywheel? I don't know much about magnets, but if i used magnets on the out side of a flywheel and the inside of the flywheel caseing which repel each other effectively crushing the flywheel to oppose centrifugal forces. Would this creat greater resistance on the rotation of the flywheel? Thanks
  25. C

    Electric field strength and particle deflection

    Homework Statement A proton enters the gap between a pair of metal plates (an electrostatic separator) that produces a uniform, vertical electric field between them. Ignore the effect of gravity on the proton. a) Assuming that the length of the plates is 11.1cm , and that the proton will...
  26. C

    Strength of electric field in fringe region vs. central region?

    Homework Statement For parallel electrodes, is the average electric field in the fringe region smaller or larger than in the central region? Homework Equations E = ΔV/ΔX The Attempt at a Solution I know that the electric field strength is proportional to the density of the...
  27. Dotini

    Strength and weight of materials

    I have a basic question concerning strength and weight of materials. Please forgive me if my question is extraordinarily naive, but I'm an elderly retiree and my education is woefully lacking in this area. Thank you for your patience and understanding. Let us say we have a block of X material...
  28. C

    Where Does the Electric Field Cancel Between Two Unequal Charges?

    Two isolated point charges -7μC and +2μC are at a fixed distance apart. At which point is is it possible for the electric field strength to be zero? I don't know where to start with only 2 numbers and no distances. I know that E= kQ/r^2
  29. A

    Field strength tensor / matrix

    In my note, we have written the field strength tensor as: F^{\mu\nu} =\partial ^\mu A^\nu -\partial ^\nu A^\mu = \begin{pmatrix} 0&E_x &E_y&E_z \\ -E_x&0 &B_z &-B_y \\ -E_y&-B_z &0 &B_x \\ -E_z&B_y &-B_x&0 \end{pmatrix} But if I look into...
  30. T

    Why is the strength of weak nuclear force important ?

    I am just a student. I read that if the strength of weak nuclear force were stronger than current value, this would cause the rarity of neutrons. And, if the strength of weak nuclear force were weaker than current value, this would cause most of hydrogen to convert to helium. I can't understand...
  31. T

    Which Law Determines the Strength of a Pull?

    Homework Statement Which law determines the strength of a pull between two objects A. Newtons first law B. Newtons second law C. Newtons law of universal gravitation D. Newtons third law Homework Equations None The Attempt at a Solution I say it is c because a pull is a...
  32. S

    What are the strength and direction of the electric field

    Homework Statement What are the strength and direction of the electric field at the position indicated by the dot in the figure Figure has been attached with the thread Homework Equations E = kq/r^2 The Attempt at a Solution My Complete Solution has been attached to the thread
  33. P

    Inertial forces, relative strength, basic q.

    The question is to rank the inertial forces, euler,coriolis and centrifugal in increasing order of strength, for a observer in the Earth' rotating frame, observing a body stationary in the UK. My thoughts are that coriolis = 2mw X (dr/dt), and so depends on the velocity so can only come into...
  34. A

    Doubt on Fatigue Strength S-N diagrams

    A standard way of plotting an S-N (fatigue strength vs no of cycles) graph is to start off by taking a value of Sm (for N=1000) cycles and joining it to the point depicting Se(Endurance Limit). Now we commonly take Sm= 0.9Sut for steels. Now I was wandering, before you actually get to use the...
  35. S

    Tensile strength of a cord winding

    Homework Statement Hi Can someone please tell me how to set equations for the following problem: A cord of length L is wound on a hollow bobbin (inner radius r and outer radius R). Cord on cord friction (static) coefficient (Ctc) and cord on bobbin (Ctb) friction (static) coefficient...
  36. T

    Physics question momentum, energy, strength of steel, PSI etc

    1.) If a car is in a frontal crash test, and goes hurling into a steel wall for instance, what unit of measure is used to define the strength of the steel wall? For instance, is the resistance strength of the steel measured in tensile strength, yield strength or something else? 2.) Another...
  37. Crazymechanic

    What is the maximum magnetic field strength for a given size permanent magnet?

    Now I'm sure one can find this at google somehow , even though I wasn't that successful with it. Does someone know what is the highest magnetic field strength for a givem size permanent magnet for example? Like a 1cm ball of neodymium or some other material, what would be the highest field...
  38. A

    Strength of magnetic field required to balance gravitational force

    Homework Statement A particle with charge q = 4.00 10-6 C and mass m = 1.30 10-4 kg is moving parallel to the Earth's surface at a speed of 1000 m/s. What minimum strength of magnetic field would be required to balance the gravitational force on the particle? Homework Equations Not...
  39. D

    Strength of Materials- Asymmetric, simply supported beam problem

    I'm working on a problem but I've hit a road block.. Then the cross section of the piece is here: The first part of the problem is to determine Iy, Iz, and Iyz of the member.. I found the y value of the centroid to be 2.8587" and the z value of the centroid to be 1.0734" using the...
  40. C

    Calculating Net Electric Field Strength at Point A

    Homework Statement Find the net electric field strength at point A due to the combined electric fields of both charges. Homework Equations E=kq/d^2 The Attempt at a Solution I know how to solve these type of problems however I'm just wondering how come in the net force line as you...
  41. Spinnor

    Size of a proton as a function of relative strength of color force?

    If we could set the strong force to be ten times weaker (compared with the electromagnetic force) how much would the radius of the proton change if any? In the limit that the strength of the strong force goes to zero does the proton radius approach some limit? Thanks for any help!
  42. MarkFL

    MHB Collin's question at Yahoo Answers regarding maximization of beam strength

    I have posted a link there to this thread so the OP can view my work.
  43. J

    Strength of 4x4 3/16' Tubing over span of 20ft with weight spread

    Hey guys I found this forum and very informative i must say. My question is i found a similar thread but i am wondering. I am building a punching bag frame for 14 punch bags between the weight of 100-120lbs. The span is 23' by 20'. The span of 23' will be broken up with a support in...
  44. G

    Do you just multiply the Yield strength by the thickness?

    The term yield strength is always bugging me deciphering the actual use in some cases. If I had a plate 3m x 2m 30mm material of Yield Strength 355N/mm², does this mean the maximum allowable force at one point on the plate is 10,650N (355 x 30mm), not taking into account safety factors...
  45. Malverin

    Increase Electromagnet Strength Without Additional Energy

    Hello, If we have an electromagnet with some lifting force, for example 10N, and make core area smaller at the ends, to concentrate the magnetic field (without saturating the core) according to the formula, for magnetic flux magnetic field density B , will be greater. For example if we...
  46. F

    Calculating Bond Energy of Steel Using Theoretical Strength Eqn

    Homework Statement Steel has a theoretical strength of 4 x 10^10 Pa a density of 7860 kg/m^3, Youngs Modulus of 2 x 10^11 Pa and the mass number of iron, the main ingredient in steel, is 56. Calculate the bond energy of the steel using the expression for theoretical strength and surface...
  47. L

    Calculating magnetic field strength through objects.

    If I have a magnetic field of say 5 Tesla which is 3m from a concrete wall 0.25m thick how would I go about calculating the strength of the magnetic field on the other side of the wall? Any help/guidance much appreciated!
  48. N

    Comparing structural bending strength

    Hello, Not sure how to go about solving this problem: What outer diameter must a 2mm thick hollow rod have in order to have the same structural bending strength as a solid rod with diameter of 7mm? Also compare the weight per unit length of the two rods. Assume that material is stainless...
  49. P

    High strength ceramic vs metals vs metal fiber composite

    metals are generally considered more useful for high strength parts because ceramics break when exposed to sudden shock, but what about when a continuous force is applied to a ceramic and a metal of the same dimensions by a high strength ceramic i mean a higher hardness than the metal (such as...
  50. 1

    Radius of Specimen from Flexural Strength

    Homework Statement A circular specimen of glass is loaded using the three-point bending method. Compute the minimum possible radius of the specimen without fracture, given that the applied load is 4000 N the flexural strength is 65 MPa, and the separation between load points is 35mm...
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