Youngs Modulus Experiment Questions and Answers

Answer-1: Young's modulus is defined as the ratio of longitudinal stress to longitudinal strain.

Answer-2: When the lengths of the rod of uniform cross section is very large compared to its breadth such that the shearing stress over any section of the rod can be neglected, the rod is called beam.

Answer-3: Due to depression, the upper or the concave side of the beam becomes smaller than the lower or the convex side of the beam. As a result, longitudinal strain is produced. The change in wave length of the beam. These forces will give rise to longitudinal stress.

Answer-4: The thickness of the bar should be measured very carefully since its magnitude is small and it occurs in the expression ?E' in the power of three. An inaccuracy in the measurement of the thickness will produce the greatest proportional error in E.

Answer-5: To keep the reaction at the knife edges equal in conformity with the theory.

Answer-6: Generally, beams run horizontally and span between columns, which are vertical, to support a load - like a floor or a roof.

Answer-7: A point on a line parallel to the axis of a beam through which any transverse force must be applied to avoid twisting of the section.

Answer-8: The elastic constants of a material describe its response to an applied stress or, conversely, the stress required to maintain a given deformation.

Answer-9: Ratio of decrease in the thickness (lateral contraction) of a body being pulled (under a tensile load) to its increase in length (longitudinal extension).It is constant for a material, around 0.28 for ordinary steels.

Answer-10: If youngs modulus = E, Shear modulus = G, Bulk Modulus = K and Poissons ratio = v then E = 3K(1-2v) E = 2G(1+v)

Answer-11: Modulus of Rigidity (or Shear Modulus) is the coefficient of elasticity for a shearing force. It is defined as "the ratio of shear stress to the displacement per unit sample length (shear strain)?.

Answer-12: The energy stored in a body due to deformation is called the strain energy.

Answer-13: The property of a material that enables it to resume its original shape or position after being bent, stretched, or compressed; elasticity

Answer-14: Proof resilience is the maximum strain energy that can be stored in a material without permanent deformation.

Answer-15: The maximum mechanical energy stored per unit volume of material when it is stressed to its elastic limit.

Answer-16: The theorem that the component in a given direction of the deflection of the point of application of an external force on an elastic body is equal to the partial derivative of the work of deformation with respect to the component of the force in that direction. Also known as Castigliano's principle

Answer-17: The slenderness ratio is the ratio between the height or length of a structural element (such as a column, or strut) and the width or thickness of the element.

Answer-18: Fatigue Failures Occur due to the application of fluctuating stresses that is much lower than the stress required to cause failure during a single application of stress.

Answer-19: Beam buckling is a distortion in shape that occurs when the load on the beam is greater than the beam is designed to carry.

Answer-20: The maximum value of stress beyond which stress is not proportional to strain. (Beyond elastic limit strain is rapid).

Answer-21: The restoring force per unit area set up inside the body which is under the influence of deforming force.
Stress (inside the body) = deforming force (externally applied)

Answer-22: The ratio of change in length (L), volume (V) or shape to the original length (L) volume (V) or shape.
l / L = longitudinal strain
v / V = cubical strain

Answer-23: Newton/meter² or dynes/cm²

Answer-24: No units since if the ratio between the similar quantities

Answer-25: N/m² or dynes/cm²

Answer-26: To eliminate the error due to change in temperature.

Answer-27: Iron, because iron can regain its original shape or length more easily than foam.

Answer-28: Yes, they have.