As part of an unmanned-autonomous-vehicle (UAV) demonstration, an unmanned vehicle B launches a projectile A from the

Question:

As part of an unmanned-autonomous-vehicle (UAV) demonstration, an unmanned vehicle B launches a projectile A from the position shown while traveling at a constant speed of 30 km/h. The projectile is launched with a speed of 70 m/s relative to the vehicle. At what launch angle θ should the projectile be fi red to ensure that it strikes a target at C? Compare your answer with that for the case where the vehicle is stationary.