solution_056d.py

#!/usr/bin/python3
# ====================================================================
# RPM
# ====================================================================

import user_interface as ui
import math

print('''
+----------------------------------------------------------+
| calculate the RPM given                                  |
|   1. tangential velocity (ft/sec) (meter/sec)            |
|   2. radius (ft) (meter)                                 |
|                                                          |
| you must use ether English or metric measurements.       |
| Do not mix them.                                         |
+----------------------------------------------------------+''')

while True:

    # ---- tangential velocity

    print()
    s = ui.get_user_input('Enter tangential velocity: ')

    if not s:
        break

    tf,t = ui.is_float(s)

    if not tf:
       print()
       print('tangential velocity')
       print(f'non-float entered ({s})')
       break

    # ---- radius

    print()
    s = ui.get_user_input('Enter radius: ')

    if not s:
        break

    tf,r = ui.is_float(s)

    if not tf:
       print()
       print('radius')
       print(f'non-float entered ({s})')
       break

    # ---- circumference

    c = 2 * math.pi * r

    # ---- rpm

    rpm = (t*60)/c

    print()
    print(f'RPM = {rpm:1.4}')

print()