Recent content by comicnabster

Never mind, solved.

Homework Statement In materials science right now we are learning about miller indices and crystallographic directions, including planes. What is the aspect ratio (height/width) of an AFM (atomic force microscope) silicon tip in the shape of a square pyramid where each face of the pyramid...

You were trying to use trigonometry and torques, which overcomplicated matters and thus got you confused. It's ok, I've had my fair share of experiences where I try to apply unneeded concepts to a problem and make things harder for myself :(

I just used what was shown here: http://www.egglescliffe.org.uk/physics/gravitation/balls/aproxg2.html Enjoy :)

Hey, I have to derive the exact same equation for my lab too O_O

I described it as a cone with the top end cut off

All right, I think I got it this time! So the stress is actually uniform throughout the column, thus it must also be 12 MPa at the top. I used integration to get the volume of the column (revolve around x-axis). Conclusion: Lower radius = 0.527 m, upper = 0.510 m

Thanks, but now I have another question - how do I find the volume of a trapezoidal cylinder prism? I know how to find the volume of a trapezoidal straight-edge prism but not for the type where the bases are two circles of different areas.

Homework Statement As quoted from the question sheet: When building a tall support, often the self weight of the support must be considered. For an optimal support, the volume of material, and hence the cost, will be a minimum. If the maximum allowable stress in concrete is 12 MPa, determine...

I need help with this question too.