# Simply Supported Beam Homework Clarification

• tsukuba
In summary, the conversation is about a homework question involving calculating deflection using the center deflection formula. The question states "19 inches from one end" and the person is unsure if they used the correct formula. They mention using the maximum deflection formula and having trouble understanding the "deflection at anysection in terms of x" formula. They ask for clarification on how to determine the values for x and b in the formula. The expert clarifies that they should refer to the diagram attached to the formula and use the longer distance for b. The conversation ends with the person stating their final answer.

## Homework Statement

Hello, I did the question but would like for someone to clarify if its right. The question states " 19 inches from one end" but I used the center deflection formula and I am not sure if its right.
It is question 2 of the picture

## Homework Equations

equation is in the picture

## The Attempt at a Solution

My solution is in the picture

tsukuba said:

## Homework Statement

Hello, I did the question but would like for someone to clarify if its right. The question states " 19 inches from one end" but I used the center deflection formula and I am not sure if its right.
It is question 2 of the picture

## Homework Equations

equation is in the picture

## The Attempt at a Solution

My solution is in the picture

Unless 19 inches is half of 6 feet 4 inches, no, you did not use the correct formula to calculate the deflection of this beam. Why did you think they put that box with a different beam formula right under the title of the problem?

I thought so, since I used the maximum deflection one. I am having a little trouble understand the formulas for "deflection at anysection in terms of x"
I think I am supposed to use y = Pbx / 6LEI ( L2-x2-b2 but I am not sure weather x is 19 and b is 57 or
x is 57 and b is 19
How would I know this?

tsukuba said:
I thought so, since I used the maximum deflection one. I am having a little trouble understand the formulas for "deflection at anysection in terms of x"
I think I am supposed to use y = Pbx / 6LEI ( L2-x2-b2 but I am not sure weather x is 19 and b is 57 or
x is 57 and b is 19
How would I know this?

Look at the diagram attached to the formula. That should tell you what to use for a and what to use for b. Notice that one distance is longer than the other.

okay, so If you look at the picture I used the first formula of the middle column where 0<x<a
I made b = 19 and from the formula to calculate x I got 42.5
My final answer is 2.289 lbs