9/5 Homework 3 is posted

[ejbarbero]

Problem 1 is another "centroid problem". It requires you to use a table. If you get stuck, ask the TA.
I don't remember which one of these...

bud98209_appa76.jpg (41.61 KiB) Viewed 637 times

bud98209_appa77.jpg (41.15 KiB) Viewed 637 times

Pb 2 is a simple Mohr problem like in 243.

Pb 3 is like in the video and PPT, review those and you can do it.

Pb 4, you need next Tuesday's lecture.

[mas00097]

I am having trouble with the assignment. For problem one I am using a 253 equation for moment of inertia of a semi-circle, but it is giving me the wrong answer according to webwork. Is there something I need to use table A-18 for that is specific to the problem?
I am also having trouble with problem two. I found theta p, and I am trying to use the theta s equation in the powerpoint but webwork says its wrong. Is theta s supposed to be in a specific direction?

[sd00002]

I am having trouble with the assignment. For problem one I am using a 253 equation for moment of inertia of a semi-circle, but it is giving me the wrong answer according to webwork. Is there something I need to use table A-18 for that is specific to the problem?
I am also having trouble with problem two. I found theta p, and I am trying to use the theta s equation in the powerpoint but webwork says its wrong. Is theta s supposed to be in a specific direction?

I used the equation (pi/8 - 8/9pi)r^4 for the I of the semi circle sub area. I was able to get the correct answer using that formula and then setting everything up in a table and using parallel axis.

As far as the direction of theta s it needs to be in the direction of your max tau.

If any one has any advice on number 4. I have gotten my shear and moment diagrams taken care of, and I got the compressive stress, but i cannot for the life of me get the tensile stress correctly.

[cmj00012]

I am having trouble with the assignment. For problem one I am using a 253 equation for moment of inertia of a semi-circle, but it is giving me the wrong answer according to webwork. Is there something I need to use table A-18 for that is specific to the problem?
I am also having trouble with problem two. I found theta p, and I am trying to use the theta s equation in the powerpoint but webwork says its wrong. Is theta s supposed to be in a specific direction?

I used the equation (pi/8 - 8/9pi)r^4 for the I of the semi circle sub area. I was able to get the correct answer using that formula and then setting everything up in a table and using parallel axis.

As far as the direction of theta s it needs to be in the direction of your max tau.

If any one has any advice on number 4. I have gotten my shear and moment diagrams taken care of, and I got the compressive stress, but i cannot for the life of me get the tensile stress correctly.

I'm also having issues with finding the maximum tensile stress for #4. I'm positive I have the right answer but Webwork is saying it's wrong. I'm not sure what other approach to take here.

[sd00002]

I am having trouble with the assignment. For problem one I am using a 253 equation for moment of inertia of a semi-circle, but it is giving me the wrong answer according to webwork. Is there something I need to use table A-18 for that is specific to the problem?
I am also having trouble with problem two. I found theta p, and I am trying to use the theta s equation in the powerpoint but webwork says its wrong. Is theta s supposed to be in a specific direction?

I used the equation (pi/8 - 8/9pi)r^4 for the I of the semi circle sub area. I was able to get the correct answer using that formula and then setting everything up in a table and using parallel axis.

As far as the direction of theta s it needs to be in the direction of your max tau.

If any one has any advice on number 4. I have gotten my shear and moment diagrams taken care of, and I got the compressive stress, but i cannot for the life of me get the tensile stress correctly.

I'm also having issues with finding the maximum tensile stress for #4. I'm positive I have the right answer but Webwork is saying it's wrong. I'm not sure what other approach to take here.

I am pretty sure I am goofing up the formula. I used the (-yM)/I but im not sure I am using it correctly for the max.

[mm00133]

Hi everyone,

I'll be in my office (ESB-1010) today until 5 PM. Feel free to drop by if you need help with problems; I'd be happy to assist!

Looking forward to seeing you.

Masoud
mm00133@mix.wvu.edu