El auto va en velocida constante en linea recta como se describe el movimiento del pendulo un observador fuera del auto y el pasajero del auto

Here's a translation: The car goes in a constant velocity in a straight line as the movement of the pendulum is described by the observer. So the movement of the pendulum should be backwards because the pendulum is not the car but it is moving just as fast, but you still have vectors of gravity pulling it downwards. 
Basically, the car is moving forward but the pendulum, at an angle (likely 45 degrees depending on the speed of the car) is tilted backwards. 

If you are trying to figure out how to say it in spanish it is.what time does the plane leaves the door a21 to phoenix?