center of percussion
perpendicular impacts at the CoP will produce no reactive shock at the pivot of a rigid beam
en-GB/ˈsɛntə əv pəˈkʌʃən/
en-US/ˈsɛnɚ ʌv pɚˈkʌʃən/
perpendicular impacts at the CoP will produce no reactive shock at the pivot of a rigid beam