Units Conversions

on the TI-89

Converting values from one unit from another is a very mechanical, methodical exercise that you need to be able to do efficiently and reliably by hand. Sometimes, though, it would be nice to have a backup, to check your work, for instance. The TI-89 calculator can do this for you. Here is how it works:

Problem:

Convert the speed 36.5 fathoms per minute to meters per second. (This is from Sample Problem 1-1 on page 3 of HRW)

1. Type 3 key6 keydecimal point key5 key.

2. Open the Units Menu by pressing 2nd3 key("Units").

3. Use the arrow keys to scroll down to "Length". Open the menu by pressing the right arrow, then select "_fath" for fathoms.
units menu

4. Press Enter and the unit will be copied to the home screen. (Note: You can type the unit from the keyboard if you know its abbreviation. The underscore "_" is found at diamond)

5. Press divide key.
home screen with "36.5 _fat/"

6. Press 2nd3 key to return to the Units Menu. Select "_min" from the "time" submenu.
selecting "min"

7. Press Enter.

8. The conversion operator is the yellow triangle above the <Mode> key. To get it, press 2nd<Mode>.
36.5_fath/_min>

9. Now, go back to the Units Menu and select "_m" from the length menu (or type it from the keyboard), and press Enter.

10. Press divide key, then select "_s" from the "Time" submenu of the Units Menu (or type it from the keyboard), and press Enter.

(Note: Actually, steps 8-10 are unnecessary in this case. If you type "36.5_fath/_min" and press enter key, it will automatically be converted to 1.11252_m/_s - as long as the default Unit System is "SI" on the mode key menu. The TI-89 automatically converts measurements to the default system.)
36.5_fath/_min>_m/_s

11. Press Enter to display the result of the calculation. That's it.
the final result
last update August 14, 2003 by JL Stanbrough