HP 15C: Static
Equivalent at a Point
Source: Step by Step
Solutions for your HP Calculator: Engineering Applications. HP-32S.
Hewlett Packard. Corvallis,
OR. 1988
pg. 40-44
Equations:
R5 * cos θ1 + R6 * cos θ2 = - Σ F * cos ϕ
R5 * sin θ1 + R6 * sin θ2 = - Σ F * sin ϕ
This program solves for R5, R6.
Variables:
Inputs:
R0: number of points
R1: T = angle of each
known force (ϕ)
R2: F = value of each
known force (F)
A = direction of the first reaction force (θ1)
B = direction of the second reaction force (θ2)
Outputs:
R5: R1 = unknown force 1
(R1)
R6: R2 = unknown force 2
(R2)
Temporary Variables:
R3, R4, R7, R8, R9, R.0
R3 = X = sin θ1
R9 = Y = cos θ1
R4 = C = sin θ2
R.0 = D = cos θ2
R7 = Σ F * cos ϕ
R8 = Σ F * sin ϕ
This program clears all the registers.
Instructions:
Enter n, press [ f ]
[1/x] ( E ), then each pair of T then [R/S] and F then [R/S],
respectively. When completed with the
pair, enter A and B. R1 is displayed
first. Press [R/S] to get R2.
Caution:
The HP 15C does not have an alpha numeric display, so you
have to keep track of everything yourself.
For register .0, press [ . ] [ 0 ].
Program:
|
Step
|
Key
|
Key Code
|
|
001
|
LBL E
|
42, 21, 15
|
|
002
|
Clear Registers [ f ] [X<>Y]
|
42, 34
|
|
003
|
STO 0
|
44, 0
|
|
004
|
LBL 1
|
42, 21, 1
|
|
005
|
R/S (enter T here)
|
31
|
|
006
|
STO 1
|
44, 1
|
|
007
|
R/S (enter F
here)
|
31
|
|
008
|
STO 2
|
44, 2
|
|
009
|
>R (Polar to
Rectangular)
|
42, 1
|
|
010
|
STO+ 7
|
44, 40, 7
|
|
011
|
X<>Y
|
34
|
|
012
|
STO+ 8
|
44, 40, 8
|
|
013
|
DSE 0
|
42, 5, 0
|
|
014
|
GTO 1
|
22, 1
|
|
015
|
R/S (enter A here)
|
31
|
|
016
|
SIN
|
23
|
|
017
|
STO 3
|
44, 3
|
|
018
|
LST X
|
44, 36
|
|
019
|
COS
|
24
|
|
020
|
STO 9
|
44, 9
|
|
021
|
R/S (enter B here)
|
31
|
|
022
|
SIN
|
23
|
|
023
|
STO 4
|
44, 4
|
|
024
|
LST X
|
43, 36
|
|
025
|
COS
|
24
|
|
026
|
STO .0 (note
the .0)
|
44, .0
|
|
027
|
RCL 7
|
45, 7
|
|
028
|
RCL* 4
|
45, 20, 4
|
|
029
|
RLC .0
|
45, .0
|
|
030
|
RCL* 8
|
45, 20, 8
|
|
031
|
-
|
30
|
|
032
|
RCL 3
|
45, 3
|
|
033
|
RCL* .0
|
45, 20, .0
|
|
034
|
RCL 9
|
45, 9
|
|
035
|
RCL* 4
|
45, 20, 4
|
|
036
|
-
|
30
|
|
037
|
÷
|
10
|
|
038
|
STO 5
|
44, 5
|
|
039
|
R/S (display R1)
|
31
|
|
040
|
LST X
|
43, 36
|
|
041
|
RCL 9
|
45, 9
|
|
042
|
RCL* 8
|
45, 20, 8
|
|
043
|
RCL 7
|
45, 7
|
|
044
|
RCL* 3
|
45, 20, 3
|
|
045
|
-
|
30
|
|
046
|
X<>Y
|
34
|
|
047
|
÷
|
10
|
|
048
|
STO 6
|
44, 6
|
|
049
|
RTN
|
43, 32
|
Examples:
Balance a vector with length 85 turned at 144°. The reactionary direction forces are 45° and
270°. In this case, n = 1, F = 85, T =
144, A = 45, and B = 270.
Key strokes:
1 [ f ] [ 1/x ] (LBL
E)
144 [ R/S ] (T)
85 [ R/S ] (F)
45 [ R/S ] (A)
270 [ R/S ] (B)
Results:
R5 = 97.2504, press
[R/S]
R6 = 118.7282
Truss:
n = 2:
T1 = 0°, F1 = 176
T2 = 135°, F2 = 100
A = 45°, B = 180°
Key strokes:
2 [ f ] [ 1/x ] (LBL
E)
0 [ R/S ] (T1)
176 [ R/S ] (F1)
135 [ R/S ] (T2)
100 [ R/S ] (F2)
45 [ R/S ] (A)
180 [ R/S ] (B)
Results:
R5 = -100 (R5), press [ R/S ]
R6 = 37.5786
I wonder would be preferable, one blog entry for each subject or one blog post that captures multiple subjects for one calculator. Comments are welcome.
Eddie
This blog is property of Edward Shore. 2016
