FE Mechanical Questions and answers (A+ graded 100% verified latest update)

FE Mechanical Question and answers (A+ graded 100% verified latest update)Area of a circle correct answer: A=πr² Area of a cylinder correct answer: A=2πrh+2πr^2 or A=2πr(h+r) Polar moment of inertia of a cylinder correct answer: basically a cylinders resistance to deformation when torque is applied Torsion stress correct answer: Forces that try to twist and bend material Pascal correct answer: 1 Pa = 1 N/m^2 SI unit of pressure Elongation correct answer: elastic longitudinal deformation the load across the length of a rod, over the strain across the area. Modulus of Elasticity correct answer: The ratio of the increment stress to the increment of strain - aka the linear slope of Stress vs Strain BEFORE deformation measured in PA Also known as... -Young's modulus -bulk modulus -shear modulus -coefficient of elasticity -elasticity modulus -elastic modulus. Polar moment of inertia of a hollow shaft correct answer: the shafts resistance to being distorted by torsion. the higher the polar moment of inertia, the greater the torsional resistance of the shaft. Mohr's Circle correct answer: graphical representation of shear and normal stresses on inclined planes Horizontal=Normal Stress (+tension, -compression) Vertical=Shear Stress (+clockwise shear, -counter clockwise shear) Recrystallization correct answer: Defected metal grains are replaced with new grains, used to soften hardened metals that became brittle through cold working -decrease in strength, ductility & hardness Recrystallization temperature correct answer: The minimum temperature at which complete recrystallization occurs within approximately 1 h. RT of alloys > RT of pure metals Cold Working correct answer: Any metalworking process that takes place BELOW a metals recrystallization temp, usually ambient. Metal grains become elongated -squeezing -bending -drawing -shearing Equiaxed grains correct answer: Grains which are approximately equal in all directions. Happens when molten metal begins to cool and the grains "grow" Anodic reaction correct answer: oxidation of metal specific gravity correct answer: ratio of a mineral's weight compared with the weight of an equal volume of water *multiply times the density Viscosity correct answer: a liquid's resistance to flow, (Pa*s) ratio of shear stress/velocity gradient kinematic viscosity correct answer: ratio of dynamic viscosity/density OR ratio of shear stress/shear deformation (m^2/s) mass flow rate correct answer: the amount of mass flowing through a cross section per unit time, (lbm/s) m dot = density*V dot cross-section area correct answer: A surface or shape exposed by making a straight cut through something at right angles to the axis. Specific Volume correct answer: Volume per unit mass; reciprocal of density Rankine Cycle correct answer: 1-2 Isentropic compression in a pump 2-3 Constant pressure heat addition in a boiler 3-4 isentropic expansion in a turbine 4-1 constant pressure heat rejection in a condenser cycle of a heat engine that converts heat into mechanical work What decreases the recrystallization temperature? correct answer: -increasing annealing time -increasing amount of cold work -smaller cold work grain size stress correct answer: the force over a surface area, can be tensile or compressive shear stress correct answer: stress in the direction of a force strain correct answer: the change in shape of an object when stress or force is applied, negative for stretching, positive for compression Modulus of Elasticity correct answer: quantifies an objects resistance to being deformed poissons ratio correct answer: material expand perpendicular to the direction of compression lateral strain over axial strain elongation correct answer: describes a linear stress/strain curve a material elongates due to light stress and returns to its shape isotropic correct answer: material with elastic properties that are independent of direction ex. glass, structural materials anisotropic correct answer: materials whose properties depend on direction ex. wood, fiber reinforced composites