Example Concerning the motion of a particle(with mass m)in terms of the force F acting on it,we denote by x(t)the position of the particle at time t,then the velocity is dx v= dr Its acceleration a(t)is a- From Newton's second law of motion ma(t)=F(t) dx F(t) d2= m 4口10y至，无2000 Ordinary Differential EquationsExample Concerning the motion of a particle (with mass m) in terms of the force F acting on it, we denote by x(t) the position of the particle at time t, then the velocity is v = dx dt Its acceleration a(t) is a = dv dt = d 2 x dt2 From Newton’s second law of motion ma(t) = F(t) d 2 x dt2 = F(t) m . Ordinary Differential Equations