# Could you please validate my answer?

• qwerty11
In summary: What is it?In summary, the problem asks for the maximum distance a painter of mass 70kg can walk on the overhanging part of a 6m plank before it tips. To solve this, the moments about the support nearest the overhang must be calculated. However, the attempted solution provided is unclear and contains errors, such as multiplying by 0 and using incorrect units. More clarification and explanation is needed in order to properly solve the problem.
qwerty11

## Homework Statement

A uniform plank of length 6.00m and mass 30.0 kg rests horizontally across two horizontal bars of a scaffold. the bars are 4.50 m apart, and 1.50m of the plank hangs over one side of the scaffold. How far can a painter of mass 70.0kg walk on the overhanging part of the plank before it tips?

w1*d-w2*d=0

## The Attempt at a Solution

70g*d*Na*0-30g+((6.2)-1.5)+Nb*4.5=0
70g*d-30g+((6/2)-1.5)=0
d=(30g*(6/2)-1.5)=0
d=0.6428m

Is my answer correct and is meters the right unit d should be in?

Your explanation is incomprehensible to me. What are you attempting to do here?

AM

That is the distance the painter can walk on the overhang park of the plank before it tips.

qwerty11 said:
That is the distance the painter can walk on the overhang park of the plank before it tips.
I understand what the question is asking. I am having difficulty understanding your work. Can you explain the steps you are taking and your reasoning? You have to find the moments about the support nearest the overhang. I don't understand how you get this:

70g*d*Na*0-30g+((6.2)-1.5)+Nb*4.5=0

For example, why do you multiply by 0 in the first term? Why are there 4 terms here and only two in your formula? Why do you subtract 30g? What is Na and Nb? What does 6.2 represent?

AM

70g should be 70kg which is the mass of the painter. Na is the weight of the plank (again should be kg instead). 6.2 should be 6/2 which is the length of the board on each side of the pivot. -1.5 is subtracting the non-overhang part out. 4.5 is the distance the bars are apart from each other.

Bump.

Bump.

70g*d*Na*0-30g+((6.2)-1.5)+Nb*4.5=0
It is still difficult to make sense of this.

The torque due to the painter is (70 kg)*g*d that appears at the beginning of your expression. It makes no sense to multiply that by the weight Na of the plank or by zero, and you have done both.

(30 kg)*g is the weight of the plank. You are adding that to the moment arm of the plank's center-of-mass, "6/2 - 1.5", but you need to multiply them in order to get the torque due to the plank's weight.

Why does the plank's weight appear twice in the equation, as Na and as 30*g?

You never explained what Nb is.

## What does it mean to validate an answer?

Validating an answer means checking its accuracy and correctness. It involves verifying the evidence and reasoning used to come up with the answer.

## Why is it important to have my answer validated?

Having your answer validated is important because it ensures that your conclusion is supported by reliable evidence and sound reasoning. It also helps to identify any errors or misunderstandings that may have occurred.

## Who is responsible for validating my answer?

As a scientist, it is your responsibility to validate your own answer. This involves critically evaluating your own work and making sure that all steps and assumptions are sound.

## What are some methods for validating an answer?

Some methods for validating an answer include peer review, replicating experiments, and using multiple sources of evidence. These methods help to ensure that the answer is accurate and unbiased.

## What should I do if my answer is not validated?

If your answer is not validated, you should revisit your evidence and reasoning to identify any errors or gaps. It may also be helpful to seek feedback from other scientists or experts in the field.

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