here is a link to the practice problems: http://courses.ncsu.edu/ce214/lec/002/problems.pdf

I am trying to figure out how to do the second problem, any help would be greatly apprecated

5/4/2006 9:41:38 PM

also help on the first problem would be apprecaited as well

5/4/2006 10:18:19 PM

i don't have time to work out the problems

but the first one should be pretty easy if you draw all your FBDs correctly

for the second problem, just find the centers of mass for the entire semi-circle and the inner polygon section

hope that helps some

[Edited on May 4, 2006 at 10:21 PM. Reason : ]

5/4/2006 10:20:59 PM

I understand the basic process for both of them.

For the first one what is the normal force of the ladder and the block streight down or at an angle, and would it be 40lb's? If it is not streight down i dont know how to find the angle it is at

For the second one how would you divide up the inner part and get proper dimentions?

Thanks though for the input though Ernie



[Edited on May 4, 2006 at 10:45 PM. Reason : ,]

5/4/2006 10:39:33 PM

a normal force always acts perpendicular to the surface, hence 'normal'

it shouldn't be 40lbs since there are two reactions, at points B and C, in addition to the weight of the block

for the second problem, use the radius of the circle and divinde the polygon into triangles:



the red lines are the radii, should be pretty easy to find the area of the polygon once you see that

[Edited on May 4, 2006 at 10:57 PM. Reason : ]

5/4/2006 10:55:29 PM

point c is frictionless so i do not belive there would be a reaction there(though correct me if i am wrong please)... but damnit that was so fucking easy, i have no idea why i didnt see thoes triangles before

thanks Ernie, your the man

5/5/2006 12:48:36 AM