Question

Ropes made of nylon and polyester are commonly used in cranes and elevators because?
A.Nylon is inflammable
B.It is good conductor of heat and electricity
C.It is very strong, fairly elastic and light weight
D.It is heat resistant.

Answer 1

Hint: The \[19\]-wire Seale strand is the most widely used strand construction for elevator ropes in the world .The Seale strand provides a higher level of resistance to external wear in use when moving over the traction sheave and deflection points due to the thick outer wires.

Complete answer:
Nylon is a synthetic fibre. It was first used on February \[28,{\text{ }}1935,\] and is one of the most widely used polyamides. Other products made from nylon include parachutes, ropes, tyre cord, carpets, fishing nets, and fabric and socks. Wallace Carothers of Du-Pont invented nylon.
Polyester is a synthetic fibre made mostly from petroleum. This fabric is one of the most widely used textiles in the world, with thousands of consumer and industrial applications. Polyester is a polymer that is mostly made up of compounds with the ester functional group.
Nylon and polyester ropes are widely used in cranes and elevators due to their strength, elasticity, and lightweight.
So option(c) is correct.

Note:
The ancient Egyptians were most likely the first civilization to create unique rope-making tools. Egyptian rope was made primarily of water reed fibres and dates from \[4000\] to \[\;3500\]BC. Other ancient ropes were made from date palm fibres, flax, grass, papyrus, fur, or animal hair.