# Calculating Tension of Rope for Scaffold with 690N Worker

• esinn08
In summary, the window washer would need to sum the forces about one end in order to get the tension.
esinn08
Hi everyone,

My question is as follows:

A window washer is standing on a scaffold supported by a vertical rope at each end. The scaffold weighs 190N and is 2.9m long. What is the tension in each rope when the 690N worker stands 1.9m from one end?

I know the sum of the forces has to be 0, since the scaffold isn't moving. I also know to get the tension you multiply the weight by the appropriate length. I'm just not sure where to go from there. Any suggestions would be greatly appreciated

esinn08 said:
Hi everyone,

My question is as follows:

A window washer is standing on a scaffold supported by a vertical rope at each end. The scaffold weighs 190N and is 2.9m long. What is the tension in each rope when the 690N worker stands 1.9m from one end?

I know the sum of the forces has to be 0, since the scaffold isn't moving. I also know to get the tension you multiply the weight by the appropriate length. I'm just not sure where to go from there. Any suggestions would be greatly appreciated

The sum of the forces AND the sum of the torques must equal zero. The scaffold weight may be represented by a single 190N force acting 1.45m from one end (that is, in the middle). The tension forces are unknown at this point, call them T_1 and T_2 (they will act UP). By summing torques (force times perpendicular distance) about one end, and setting them equal to zero, watching your plus and minus signs (clockwise is plus and counterclockwise is minus), you can solve for one of the tension forces, and then the other by noting sum of all forces in vertical direction is 0.

(I made a typo in my question, the scaffold is 690N and the person is 190N.)

Regardless, I am not sure that I am completely understanding what you wrote.

(1.45m)(-690N) + (T_1)(1.45m) = 0

(1.9m)(-190N) + (T_2)(1.0m) = 0

I have a feeling that is not right. Any more suggestions?

## 1. How do you calculate the tension of a rope for a scaffold with a 690N worker?

To calculate the tension of a rope, you need to know the weight of the worker (690N), the angle of the rope, and the number of ropes supporting the scaffold. Then, you can use the formula T = W/cos(θ) * n, where T is the tension in the rope, W is the worker's weight, θ is the angle of the rope, and n is the number of ropes.

## 2. What is the angle of the rope in this calculation?

The angle of the rope refers to the angle between the rope and the horizontal surface. This angle is important to consider because it affects the amount of tension in the rope.

## 3. How many ropes are usually used to support a scaffold with a 690N worker?

The number of ropes used to support a scaffold with a 690N worker depends on the design and weight capacity of the scaffold. Typically, scaffolds are supported by 2-4 ropes, but this can vary depending on the specific situation.

## 4. What units are used to measure tension?

Tension is typically measured in Newtons (N) or pounds (lbs). In this calculation, the tension will be measured in Newtons since the worker's weight is given in Newtons.

## 5. How important is it to accurately calculate the tension of the rope for scaffolding?

It is extremely important to accurately calculate the tension of the rope for scaffolding as it ensures the safety and stability of the scaffold. Too much or too little tension can result in the rope breaking or the scaffold collapsing, which can be dangerous for the worker and those around them. It is crucial to follow proper calculations and safety guidelines when setting up scaffolding.

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