A humanitarian helicopter of total mass 11 500 kg (pilots and food boxes) releases vertically a 150 kg box of food. The helicopter is flying at a constant speed of 45 m/s in the x-direction. Find the box's velocity immediately after it was released.

A truck with a mass of 9000 kg is moving at a constant velocity of 20 m/s. A sandbag weighing 1000 kg initially stationary falls vertically and lands in the back of the truck. What is the new velocity of the truck after catching the sandbag?