ADU Strength of Materials Questions

IECEP-Manila Form 1 S.2011 TEST QUESTIONS

PROFILE OF CONTRIBUTORName of School Adamson University

Address 900 San Marcelino Street, Ermita, Manila

Signature over Printed Name , Position

Engr. Rex Jason H. Agustin ECE Faculty

Area of Specialization Strength of Materials

Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A hole is to be punched out of plate having a shearing strength of 40 ksi. The compressive stress in the punch is limited to 50 ksi. Compute the maximum thickness of plate from which a hole 2.5 inches in diameter can be punched.

Choices:

a. 0.500 in b. 0.781 in c. 0.102 in d. 0.204 inANSWER:b. 0.781 in

SOLUTION ( IF PROBLEM -SOLVING)

t = 2.5(50) / 4(40) = 0.781 inches

Reference: Strength of Materials, Fourth Edition By Andrew Pytel and Ferdinand Singer Page 17

Endorsed by:

Engr. Evelyn Q. RaguindinSchool Representative IECEP Manila







Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A hole is to be punched out of plate having a shearing strength of 40 ksi. The compressive stress in the punch is limited to 50 ksi. If the plate is 0.25 inches thick, determine the diameter of the smallest hole that can be punched/

Choices:

a. 0.800 in b. 0.871 in c. 0.435 in d. 0.600 inANSWER:a. 0.800 in


D = 4(0.25)(40) / 50 = 0.800 inches


Endorsed by:








Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A large pipe, called a penstock in hydraulic work, is 1.5 m in diameter. It is composed of wooden staves bound together by steel hoops, each 300 sq. Millimetre in cross-sectional area, and is used to conduct water from a reservoir to power a house. If the maximum tensile stress permitted in the hoops is 130 MPa, what is the maximum spacing between hoops under a head of water of 30 m?

Choices:

a. 17.7mm b. 77.1 mm c. 177 mm d. 71.7 mmANSWER:c. 177 mm


(1000)(9.81)(30)(1.5)L = 2(300x10^-6)(130x10^6)L = 177 mm


Endorsed by:








Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:At what angular velocity will the stress in a rotating steel ring equal to 150 MPa if its mean radius is 220 mm? The density of the steel is 7.85 Mg/m^3.

Choices:

a. 19.87 rad/s b. 159 rad/s c. 138.2 rad/s d. 628 rad/sANSWER:d. 628 rad/s


ω = (1/0.22)(150x10^6 / 7850)^(1/2) = 628 rad/s


Endorsed by:Engr. Evelyn Q. RaguindinSchool Representative IECEP Manila







Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A pipe carry steam at 3.5 MPa has an outside diameter of 450 mm and a wall thickness of 10 mm. A gasket is inserted between the flange at one end of the pipe and a flat plate use to cap the end. How many 40-mm-diameter bolts must be used to hold the cap on if the allowable stress in the bolts is 80 MPa, of which 55 MPa is the initial stress?

Choices:

a. 14 b. 15 c. 16 d. 17ANSWER:d. 17


N = (3.5x10^6)(0.45 – 2x0.01)^2 / [(0.04^2)(88–55)x10^6] = 16.18 round upN = 17









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A pipe carry steam at 3.5 MPa has an outside diameter of 450 mm and a wall thickness of 10 mm. A gasket is inserted between the flange at one end of the pipe and a flat plate use to cap the end. What circumferential stress is developed in the pipe?

Choices:

a. 75.3 MPa b. 37.65 MPa c. 78.75 MPa d. 39.38 MPaANSWER:a. 75.3 MPa


σ = (3.5)(450 – 2x10) / [2(10)] = 75.3 MPa









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:It is the maximum safe stress that a material can carry

Choices:

a. working stress b. Ultimate stress c. rupture strength d. Yield strengthANSWER:a. working stress










Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:It is the point at which there is an appreciable elongation of the material without any corresponding increase of load

Choices:

a. Elastic limit b. Yield point c. Ultimate stress d. Point of ruptureANSWER:b. Yield point










Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:This component measures the pulling (or pushing) action perpendicular to the section

Choices:

a. Torque b. Bending moment c. Axial forces d. Shearing forceANSWER:c. Axial forces










Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A steel rod having a cross-sectional area of 300 sq. Meters and a length of 150 m is suspended vertically from one end. It supports a tensile load of 20 kN at the lower end. If the unit mass of steel is 7850 kg/m^3 and E = 200x10^3 MN/m^2, find the total elongation of the rod.

Choices:

a. 54.3 mm b. 40 mm c. 43.3 mm d. 35 mmANSWER:a. 54.3 mm


δ = [(7850)(9.8)(150^2) / 2(200X10^9)] + [(20000)(150)(1000^2) / 300(200X10^9)]δ = 54.3 mm









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:What is the theoretical maximum value of Poisson’s ratio of any given material subjected to a uniform triaxial stress.

Choices:

a. 0 b. 1 c. 1/3 d. 1/2ANSWER:d. 1/2










Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A steel bar 50 mm in diameter and 2 m long is surrounded by a shell of cast iron 5 mm thick. Compute the load that will compress the combined bar a total of 0.8 mm in the length of 2m. For steel E = 200 GPa, and for cast iron E = 100 GPa

Choices:

a. 291 kN b. 240 kN c. 192 kN d. 420 kNANSWER:c. 192 kN


P = [(π/4)(0.05^2)(200x10^9)(0.0008)/2] + [(π/4)(0.06^2 -0.05^2)(100x10^9)(0.0008)/2]P = 192 kN









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A solid steel shaft 5 m long is stressed to 80 MPa when twisted through 4 degrees. Using G = 83 GPa, compute the shaft diameter.

Choices:

a. 104 mm b. 138 mm c. 148 mm d. 160 mmANSWER:b. 138 mm


r = (80)(5) / [(4)(π/180)(83000)] = 69 mmd = 2(69) = 138 mm









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A solid steel shaft is not to twist through more than 3 degrees in a 6 m length when subjected to a torque of 12 kN.m. What maximum shearing stress is developed? Use G=83GPa.

Choices:

a. 41.3 MPa b. 43.4 MPa c. 34.3 MPa d. 17.6 MPaANSWER:a. 41.3 MPa


(π/4)d^4 = (12000)(6) / [(3)(π/180)(83x10^9)]d = 114 mm

τ = 16(12000) / [π(.114)^3]τ = 41.3 MPa









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:What is the minimum diameter of a solid steel shaft that will not twist through more than 3 degrees in a 6 m length when subjected to a torque of 12 kN.m? Use G=83GPa.

Choices:

a. 114 mm b. 116 mm c. 118 mm d. 120 mmANSWER:a. 114 mm


(π/4)d^4 = (12000)(6) / [(3)(π/180)(83x10^9)]d = 114 mm









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:A steel rod 2.5 m long is secured between two walls. If the load on the rod is zero at 20 degree Celsius, compute the stress when the temperature drops to -20 degrees Celsius. The cross-sectional are if the rod is 1200 sq. mm, coefficient of linear expansion = 11.7 um/(m-deg.C), and E = 200 GPa. Assume that the walls are rigid.

Choices:

a. 69.3 MPa b. 96.3 MPa c. 93.6 MPa d. 69.3 MPaANSWER:c. 93.6 MPa


σ = (200x10^9)(11.7x10^-6)(20 - -20) = 93.6x10^6 Paσ = 93.6 MPa









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:Determine the maximum shearing stress in a helical steel spring composed of 20 turns of 20 mm-diamter wire on a mean radius of 80 mm when tha spring is supporting a load of 2 kN. Use G = 83 GPa.

Choices:

a. 110.6 MPa b. 112.3 MPa c. 120.6 MPa d. 134.6 MPaANSWER:c. 120.6 MPa


m = 80/10 = 8

τ = [16(2000)(0.08) / π(0.02)^3]x{[4(8)-1]/[4(8)-4] + (0.615/8)}τ = 120.6 MPa









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:Determine the elongation in a helical steel spring composed of 20 turns of 20 mm-diamter wire on a mean radius of 80 mm when tha spring is supporting a load of 2 kN. Use G = 83 GPa.

Choices:

a. 87.9 mm b. 78.9 mm c. 98.7 mm d. 89.7 mmANSWER:c. 98.7 mm


δ = 64(2000)(0.08^3)(20) / [(83x10^9)(0.02^4)]δ = 98.7 mm









Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:These are components of the total resistance to sliding the portion to one side of the exploratory section past the other.

Choices:

a. Torque b. Bending moment c. Axial forces d. Shear forcesANSWER:d. Shear forces










Please indicate the subject:(x) General Engineering and Applied Science ( ) Electronics System & TechnologiesQUESTION:Who first postulated that stress is proportional to strain in 1678?

Choices:

a. Thomas Young b. Robert Hooke c. Andrew Pytel d. Charles AugustusANSWER:c. Robert Hooke




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ADU Strength of Materials Questions