solution_056c.py

#!/usr/bin/python3
# ====================================================================
# radius
# ====================================================================

import user_interface as ui
from math import sqrt

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

while True:

    # ---- centripetal acceleration

    print()
    s = ui.get_user_input('Enter centripetal acceleration: ')

    if not s:
        break

    tf,a = ui.is_float(s)

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

    # ---- tangential velocity

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

    if not s:
        break

    tf,v = ui.is_float(s)

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

    # ---- tangential velocity

    r = v**2/a

    print()
    print(f'radius = {r:1.4}')

print()