fɚðə mᵻkˈænɪkəl ˈɪmpækt ɛɡzˈæmpəl, ɪf wiː dˌɪfɚɹˈɛnʃɪˌeɪt wˈʌns wiː hˈæv , wˌɪtʃ dʌznˌɑːt jˈɛt ɛksplˈɪsɪtli ɪnvˈɑːlv .
For the mechanical impact example, if we differentiate  once we have , which does not yet explicitly involve .