howdy - hope dis aint 2 late!! [its 2003 q 17]
A=4(pie)d*2
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4
Stress=Load
-------
Area
450x10*6 =5x70x10*3
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(pie)d*2
d*2 = 5x70x10*3
-------------------
450x10*6x(pie)
d*2 = 2.476x10*-4
therefore
D = 0.016m
D = 16mm
b.t.w - (*) denotes "to the power of"
for example:
4*7 = 4 to the power of 7
- hope this helps - GOOD LUCK!!!!!!!