1.(a) (v_Q)_hyp = 7.80 km/s, (v_Q)_ell = 3.95 km/s, (v_P)_ell = 6.32 km/s. (b) t_QP = 2.27 hours

2. T_AB = 111.4 N, T_BC = 19.51 N

3. A. (d). B. (b). C. (e).

4. See text.