math help, page-59

Hi , PI in this example is PI as we know it IMO i.e 3.14 etc.

I think the equation is correct in total and the right answer for Q is given IMO.

We are given the figiure in the example for J. J equals PI/32(D^4-d^4). Using the numbers, if we take PI as 3.14, it goes as follows: 3.14/32 =.098125. Taking D in the example as 5 and d as 4.365, we get D^4 as 625 & d^4 as 363. Therefore the equation for J = .098125x(625-363) =25.71 rounded, which equals near enough the value of J given in the example (due to rounding).

The equation can therefore be simplfied as:

Q= ((.096167*J)/D))*Square root ((Ym*Sf)^2-(P^2/A^2))

I know nothing aabout engineering but here is a good link regarding these calculations: http://www.api.org/publications-standards-and-statistics/standards-addenda-and-errata/standards-addenda-and-errata/~/media/67a5e509bac14fc78c215ed0aa24ccbc.ashx

Cheers