HP 35s Manual

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HP 35s General applications – Part 2
Other applications
Practice solving problems
- Application 1: Aerodynamics
Example 1: Turn radius and Turn rate
-Application 2: Electrical Engineering
Example 1: Parallel Resistors
-Application 3: Civil Engineering
Example 1: Rainfall runoff

hp calculators
HP 35s General applications – Part 2
hp calculators - 2 - HP 35s General applications Part 2- Version 1.0
General applications
This training aid will illustrate the application of the HP 35s calculator to several problems in other areas. These
examples are far from exhaustive, but do indicate the incredible flexibility of the HP 35s calculator.
Practice solving problems
Application 1: Aerodynamics
Example 1: An airplane is in a steady coordinated turn with a true airspeed of 250 mph at a 40 degree bank angle.
What is the turn radius in feet and the turn rate in degrees per second?
The equations are:
Turn Radius = Velocity 2÷ ( g x TAN ( angle ) )
Turn Rate = g x TAN ( angle ) ÷ Velocity
Where g is 32.2 feet per second per second
Solution: First, convert the speed to feet per second for unit consistency.
In RPN mode: 250Ï5280¸
60¯60¯
Ï (Save for next calculation)
º=32Ë2Ï40q¸¯ (Radius in feet)
w32Ë2Ï40q¸ (Rate of turn in degrees
w¯º´ persecond)
In algebraic mode: º=250¸5280
¯60¯60Õ¯4
32Ë2¸q40Ï (Radius in feet)
º´32Ë2¸q40¯
4250¸5280 (Rate of turn in degrees
¯60¯60Ï per second)
Figure 1
Answer: The turn radius is just under 4976 feet and the rate of turn is approximately 4.22 degrees per second.
Figure 1 (RPN mode) shows the radius on the second level of the stack and the rate on the bottom level.

hp calculators
HP 35s General applications – Part 2
hp calculators - 3 - HP 35s General applications Part 2- Version 1.0
Application 2: Electrical Engineering
Example 1: Three resistors of 200 ohms, 500 ohms and 220 ohms are in parallel. What is the equivalent resistance?
Solution: In RPN mode: 200,500,Ù220,Ù,
In algebraic mode: ,,200ÕÙ,500ÕÙ,220Ï
Figure 2
Answer: The equivalent resistance is 86.6 ohms
Application 3: Civil Engineering
Example 1: Runoff of rainfall from an area to an outlet will be at maximum when the water from the most remote point
contributes to the flow. What is that time if the slope is 0.25 per foot per foot, the rain intensity is 0.8 inches
per hour and the distance from the most remote area is 800 feet. Use a coefficient of 2.1 for grass.
The formula is: Time = C x ( D ÷ ( S x I 2) ) 1/3
Where C is the grass coefficient, D is the distance from the most remote area, S is the slope, and I is the
rainfall intensity.
Solution: In RPN mode: 2Ë1Ï800Ï
0Ë25Ï0Ë8º=¸¯3¹'¸
In algebraic mode: 2Ë1¸¹'3Õ800¯
40Ë25¸º=0Ë8Ï
Figure 3
Answer: The time until maximum is just under 36 minutes.