Two locomotives approach each other on parallel tracks. each has a speed of v = 80 km/h with respect to the ground. if they are initially d = 9.0 km apart, how long will it be before they reach each other? (min)

During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. if the trebuchet launches the stones with a velocity of at an angle of 50.0°, (a) how long does it take the stone to hit the ground? (b) what is the maximum distance that the trebuchet can be from the castle wall to be in range? (c) how high will the stones go? show all your work.