# Machine Design Questions and Answers – Stresses in Wire Ropes

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This set of Machine Design Multiple Choice Questions & Answers (MCQs) focuses on “Stresses in Rope Wires”.

1. The wire rope is subjected to
a) Tensile Stress
b) Bending Stress
c) Both bending and tensile stress
d) None of the listed

Explanation: There is direct tensile stress due to load being raised as well as bending stress.

2. In design of wire ropes, bending stress is converted into an equivalent bending load which is given by [d= diameter of individual wire and D= diameter of sheave].
a) AEd/D
b) 2AEd/D
c) AEd/2D
d) None of the listed

Explanation: P=σA and σ=Ed/D.

3. An elevator is assembled to raise equipment to a height of 22m. It is estimated that maximum weight of the material to be raised is 4.9kN. It is observed acceleration in such cases is 1.2m/s².10mm diameter wire ropes with fibre core are used. The tensile designation of the wire is 1500. Number of wire ropes can be taken 2. Calculate the weight of material raised by each load.
a) None of the listed
b) 2450N
c) 4900N
d) 9800N

Explanation: Weight of material raised by each rope= 4.9/2.

4. An elevator is assembled to raise equipment to a height of 22m. It is estimated that maximum weight of the material to be raised is 4.9kN. It is observed acceleration in such cases is 1.2m/s².10mm diameter wire ropes with fibre core are used. The tensile designation of the wire is 1500.Number of rope wires is assumed to be 2. Calculate the weight of wire if weight of 50m wire is 18kg.
a) 19.36N
b) 90.25N
c) 77.70N
d) 56.66N

Explanation: W=mass per unit length x length x g.

5. An elevator is assembled to raise equipment to a height of 22m. It is estimated that maximum weight of the material to be raised is 4.9kN. It is observed acceleration in such cases is 1.2m/s².10mm diameter wire ropes with fibre core are used. The tensile designation of the wire is 1500.Number of rope wires is assumed to be 2. Number of rope wires is assumed to be 2. Calculate the weight of wire if weight of 50m wire is 18kg. Calculate the force due to acceleration.
a) 1000N
b) 309.144N
c) 504.225N
d) 102.225N

Explanation: Mass of material raised by each wire rope= 2450/9.81 = 249.7kg. Mass of each wire rope= 77.7/9.81 =7.92kg. Force due to acceleration= [249.7+7.92] x 1.2.

6. An elevator is assembled to raise equipment to a height of 22m. It is estimated that maximum weight of the material to be raised is 4.9kN. It is observed acceleration in such cases is 1.2m/s².10mm diameter wire ropes with fibre core are used. The tensile designation of the wire is 1500.Number of rope wires is assumed to be 2. Number of rope wires is assumed to be 2. Calculate the total load on wire rope neglecting the bending load if weight of 50m wire is 18kg.
a) 1054.55N
b) 3504.55N
c) 2836.84N
d) 5678.6N

Explanation: F=4900/2 + 77.7 + 249.7×1.2 + 7.92×1.2.

7. Small sheaves are preferred over large sheaves on what parameters?
a) Increasingly centrifugal force in large sheaves
b) Higher cost of small sheaves
c) Preferring centrifugal force reduction even for more money
d) None of the listed

Explanation: Larger sheaves have higher centrifugal forces and higher cost because more material is used in their construction.

8. Rope operating over steel sheaves wear slowly than those used in conjunction with cast iron sheaves.
a) True
b) False

Explanation: Rope operating over steel sheaves wear faster. If wear on cast iron sheave is 100, than wear on steel sheave is 110.

9. Which type of rope drum is preferred?
a) Drums with helical grooves
b) Plain cylindrical drums
c) Both are equally preferred
d) None of the listed

Explanation: They have more bearing surface of the drum and prevent friction between adjacent turns of the rope.

10. If nominal diameter of the rope is 20mm, then pitch of the groove is around?
a) 2mm
b) 22mm
c) 40mm
d) 10mm