HP 50g Graphing Calculator - Manual (Page 755)

Page 22-40
To find the values of the stresses corresponding to a rotation of 35
o
in the angle
of the stressed particle, we use:
$š Clear screen, show PICT in graphics screen
@TRACE @(x,y)@. To move cursor over the circle showing φ and (x,y)
Next, press ™ until you read φ = 35. The corresponding coordinates are
(1.63E0, -1.05E1), i.e., at φ = 35
o
, σ’
xx
= 1.63 kPa, and σ’
yy
= -10.5kPa.
An input form for the Mohr’s circle program
For a fancier way to input data, we can replace sub-program INDAT, with the
following program that activates an input form:
« “MOHR’S CIRCLE” { { “ σx:” “Normal stress in x” 0 } {
“
σy:” “Normal stress in y” 0 } { “τxy:” “Shear stress” 0}
} { } { 1 1 1 } { 1 1 1 } INFORM DROP »
With this program substitution, running @MOHRC will produce an input form as
shown next:
Press @@@OK@@@ to continue program execution. The result is the following figure: