Adicionada por douglas max on 9 00, 2007 at 18:30:38:
eu tenho a versão do livro em ingles, mas como não sei muita coisa nesse idioma vou postá-lo em ingles msm.
1.13. Point A moves uniformly with velocity v so that the vector v is continually "aimed" at point B which in its turn moves rectilinearly and uniformly with velocity u < v. At the initial moment of time v(parallel)u and the points are separated by a distance l. How soon will the points converge?