When to use single long rope and double short rope for towing

[Lawrence_Chehimi]

Just thinking about the above scenario, and trying to link it with physics behind doubling a rope.. @Thomas Varghese might actually have a point. Not sure if you guys know, but doubling a rope actually doubles its capacity, so a 10T rope can lift a 20T load when doubled, now assuming you are using a kinetic rope here with 20%-30% elastisity, when doubled, the force required to acheive the elasticity is Much higher and thus the kinetic energy stored increases to double.. so actually doubling the rope in certain situations can actually help. ( As far as you have enough force to make that rope strech when doubled)

 

[Thomas Varghese]

1 minute ago, Lawrence_Chehimi said:

Just thinking about the above scenario, and trying to link it with physics behind doubling a rope.. @Thomas Varghese might actually have a point. Not sure if you guys know, but doubling a rope actually doubles its capacity, so a 10T rope can lift a 20T load when doubled, now assuming you are using a kinetic rope here with 20%-30% elastisity, when doubled, the force required to acheive the elasticity is Much higher and thus the kinetic energy stored increases to double.. so actually doubling the rope in certain situations can actually help. ( As far as you have enough force to make that rope strech when doubled)

 

I had the same doubt and that's why I posted this discussion. Unfortunately all these physics were studied 35 years before and never put it into practical situations but was troubling my mind since witnessing the pull. The pulling car was on a downslope and the pull was directed down. The rope will pull only after reaching the maximum elasticity - till that time it will only stretch. Now the picture is more clear. Even though Angela @Foxtrot Oscar doubled the rope for increased maneuverability my car moved so easily from the stuck because the stored kinetic energy doubled to ease the pull. @Lawrence_Chehimi you cleared the doubt. 

My doubt was why didn't my car even budge when pulled by a single rope but moved like it was cutting through butter when it was doubled. The answer is the kinetic rope when doubled aids the pull because the stored kinetic energy doubles because the rope is elastic and when released halves the effort. (Probably that maybe the reason these elastic ropes are named kinetic ropes) I suppose an ordinary rope wouldn't have facilitated this as the kinetic energy stored doesn't increase as it doesn't have the elasticity. Same should be the case with a steel rope too. 

[GauravSoni]

@Thomas Varghese you can understand the physics here 

Jump To 6:00 for demo specific to cars!

Edited March 13, 2021 by GauravSoni

[Thomas Varghese]

7 minutes ago, GauravSoni said:

@Thomas Varghese you can understand the physics here 

 

So now our marshals start carrying pulleys with them? Sounds crazy but a great idea as it will ease the effort required to tug out heavier cars. 

[Thomas Varghese]

@Gaurav Soni I doubt the principle of the pulleys worked in the tug as the load was unidirectional. Both ends of the rope was anchored to the same points. I think it was the kinetic energy stored in the rope doubled when the rope was doubled and made the tug easy. For the principle of pulleys there should be a point where the force is split in 2 different directions. Please clarify if I'm wrong in my assumptions.