It was Alfred George Greenhill who taught MacMahon at the Royal Military Academy at Woolwich and Greenhill 's interests at that time had a large influence on MacMahon's early work. Greenhill was trying to construct a model of the trajectory of a missile based on experiments which suggested that the resistance varies as the cube of the velocity.
Ito ay Alfred George Greenhill na nagtuturo MacMahon sa Royal Military Academy sa Woolwich at Greenhill 's interes sa panahon na nagkaroon ng isang malaking impluwensiya sa MacMahon ng maaga sa trabaho. Greenhill ay sinusubukan upang bumuo ng isang modelo ng tilapon ng isang misil batay sa mga eksperimento na iminungkahi na ang paglaban nag-iiba na ang kubo ng bilis.