A pendulum is in vertical position when put it in a stopped car. What will happen when the car start to accelerate with acceleration a? The car will swing with new equilibrium position. The following applet will show you the case: You can change the acceleration a and the drag coefficient (assume drag force propotional to velocity put in the oppositive direction)
VIEW or DOWNLOAD ejs xml source
then click to translate strings for selected locale.

Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.