Consider a heavy car submerged in water in a lake with a flat bottom. The driver's side door of the car is 1.1 m high and 0.9 m wide, and the top edge of the door is 10 m below the water surface. Determine the net force acting on the door(normal to its surface) and location of the pressure center if (a) the car is well-sealed and it contains ari at atmospheric pressure and (b) the car is filled with water.