In cold weather, meteorologists report an index called the wind chill factor, which takes into account the wind speed and the temperature. The index provides a measure of the chilling effect of wind at a given air temperature. Wind chill may be approximated by the following formula,

where

v = wind speed in m/sec

t = temperature in degrees Celsius: t <= 10

W = wind chill index (in degrees Celsius)

Write a function that returns the wind chill index. Your code should ensure that the restriction on the temperature is not violated. Look up some weather reports in back issues of a newspaper in your library and compare the wind chill index you calculate with the result reported in the newspaper.