MCQs on Stresses in Wire Ropes
1 - Question
The wire rope is subjected to
a) Tensile Stress
b) Bending Stress
c) Both bending and tensile stress
d) None of the listed
View Answer
Answer: c
Explanation: There is direct tensile stress due to load being raised as well as bending stress.
2 - Question
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
View Answer
Answer: a
Explanation: P=σA and σ=Ed/D.
3 - Question
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
View Answer
Answer: b
Explanation: Weight of material raised by each rope= 4.9/2.
4 - Question
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
View Answer
Answer: c
Explanation: W=mass per unit length x length x g.
5 - Question
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
View Answer
Answer: b
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 - Question
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
View Answer
Answer: c
Explanation: F=4900/2 + 77.7 + 249.7×1.2 + 7.92×1.2.
7 - Question
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
View Answer
Answer: a
Explanation: Larger sheaves have higher centrifugal forces and higher cost because more material is used in their construction.
8 - Question
Rope operating over steel sheaves wear slowly than those used in conjunction with cast iron sheaves.
a) True
b) False
View Answer
Answer: b
Explanation: Rope operating over steel sheaves wear faster. If wear on cast iron sheave is 100, than wear on steel sheave is 110.
9 - Question
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
View Answer
Answer: a
Explanation: They have more bearing surface of the drum and prevent friction between adjacent turns of the rope.
10 - Question
If nominal diameter of the rope is 20mm, then pitch of the groove is around?
a) 2mm
b) 22mm
c) 40mm
d) 10mm
View Answer
Answer: b
Explanation: p= d + 2 mm.