# How can i find breaking strength of steel, if it's possible at all?

• exibo177
In summary, the conversation discusses the calculation of the maximum height a steel rope or rod could achieve while hung between the Earth and the Moon. The problem involves considering various factors such as the tensile strength and modulus of elasticity of steel, the distance between the Earth and the Moon, and the gravitational force. The conversation also mentions the use of a common rope with a breaking strength of 100,000 pounds and a weight of 1.85 pounds per foot. However, even with the strongest available rope, it is not possible to reach the Moon due to the limitations of the materials and the uniform gravitational field assumption. The conversation ends with a question about the connection between density, volume, and tensile strength of steel in the calculation.
exibo177

## Homework Statement

For my project I need to calculate the maximum height that a Steel Rope could achieve while being hung between the Earth and the Moon.

## Homework Equations

Tensile Strength of Steel is: 500*10^6
E of steel is: 200*10^9
distance from the Moon to he Earth is 406700

## The Attempt at a Solution

i tried a lot of stuff like used the equation F/A=E*strain (where i got strain 2.5*10^15) but nothing goes right so help me if you can!

Are we assuming a constant gravity, or are we doing the math to figure out what it really is, knowing that for part of the way the moon's gravity will be stronger.

Also, with a wire rope the calculations are entirely different than for a steel rod. E means nothing in a rope because its stretching mechanism is much more complicated. So you need to decide which rope you are using, because each rope you can buy will be different. But if you look up the numbers in the rope manufacture's technical manual, the calculations will turn out to be much easier than you at first would think.

we chose to do just math, i guess i would prefer to have a steel rod AND wire rope (i'm sorry for not mentioning it in the question). But i still don't understand how to calculate the critical point at which this rope/rod would break, so any type of help would be wonderful please. (with explanations)

If you want to start somewhere make use of the ultimate tensile strength you have been given.
500 x 10^6 means that a force of 500 x 10^6 N on a steel bar of area of 1m^2 will 'break' the steel.
The problem now is...how long a rod of steel of cross section area 1m^2 needs to be to produce a weight of 500 x 10^6N.
You need to know the density of steel.
This is all assuming that the force of gravity does not change as height increases...it does of course...but see what length you get and decide whether the decreasing force of gravity will make much difference.

So much so good for a rod. For the rope, let's select a very common rope used in the rigging industry. 6 x 37 IWRC XIPS, one inch diameter. It has a very convenient generic breaking strength of 100,000 pounds and a weight of 1.85 pounds per foot.

So how long does it have to be to weigh 100,000 pounds and break its connection at the top? Divide it out and you get a length of 54,000 feet. Figure that you used a common swaged flemish eye as an end connection, with an efficiency of 85%. So now you are down to only 46,000 feet. That is a length short enough to make your uniform gravitational field assumption reasonable, and far short of the moon.

If you used a dyform rope with XXIPS steel, the best and strongest available, you might be able to find a rope with a 30% higher strength. But it won't change the results. You are still not even going to get out of the atmosphere, let along anywhere close to the moon.

truesearch said:
If you want to start somewhere make use of the ultimate tensile strength you have been given.
500 x 10^6 means that a force of 500 x 10^6 N on a steel bar of area of 1m^2 will 'break' the steel.
The problem now is...how long a rod of steel of cross section area 1m^2 needs to be to produce a weight of 500 x 10^6N.
You need to know the density of steel.
This is all assuming that the force of gravity does not change as height increases...it does of course...but see what length you get and decide whether the decreasing force of gravity will make much difference.

Pkruse said:
So much so good for a rod. For the rope, let's select a very common rope used in the rigging industry. 6 x 37 IWRC XIPS, one inch diameter. It has a very convenient generic breaking strength of 100,000 pounds and a weight of 1.85 pounds per foot.

So how long does it have to be to weigh 100,000 pounds and break its connection at the top? Divide it out and you get a length of 54,000 feet. Figure that you used a common swaged flemish eye as an end connection, with an efficiency of 85%. So now you are down to only 46,000 feet. That is a length short enough to make your uniform gravitational field assumption reasonable, and far short of the moon.

If you used a dyform rope with XXIPS steel, the best and strongest available, you might be able to find a rope with a 30% higher strength. But it won't change the results. You are still not even going to get out of the atmosphere, let along anywhere close to the moon.
Does it have any connection with density, volume, tensile strength of steel or anything else? or did you just use the number given out by the company that produces those ropes?

## 1. What is the definition of breaking strength?

Breaking strength, also known as tensile strength, is the maximum amount of stress that a material can withstand before it breaks or fractures.

## 2. Is it possible to determine the breaking strength of steel?

Yes, it is possible to determine the breaking strength of steel through various testing methods such as tensile testing, compression testing, and impact testing.

## 3. What factors affect the breaking strength of steel?

The breaking strength of steel can be affected by factors such as the type and grade of steel, the manufacturing process, temperature and environmental conditions, and the presence of defects or imperfections in the material.

## 4. How can I calculate the breaking strength of steel?

The breaking strength of steel can be calculated by dividing the maximum load that the material can withstand by its cross-sectional area. This is known as the ultimate tensile strength (UTS) and is measured in units of force per area, such as psi or MPa.

## 5. How can I ensure the accuracy of breaking strength measurements for steel?

To ensure accurate breaking strength measurements for steel, it is important to follow standardized testing procedures and use calibrated equipment. It is also important to consider the potential for errors and conduct multiple tests to obtain an average value.

• Introductory Physics Homework Help
Replies
1
Views
3K
• Introductory Physics Homework Help
Replies
5
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
877
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
2
Views
3K
• Introductory Physics Homework Help
Replies
1
Views
4K
• Introductory Physics Homework Help
Replies
6
Views
4K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
5
Views
18K
• Introductory Physics Homework Help
Replies
1
Views
5K