Surely you have seen equation 1 (but perhaps with a slightly different notation). Each dot above an x represent a time derivative. So, the left-hand side is th

Surely you have seen equation 1 (but perhaps with a slightly different notation). Each dot above an x represent a time derivative. So, the left-hand side is the second derivative of the position with respect to time aka the acceleration, times the mass. So, the first equation is simply F = ma (but, yeah... the notation can easily throw one off if one has not see it before.)