A helium-filled balloon is tied to the floor of a car that makes a sharp right turn. Does the balloon tilt while the turn is made? If so, which way? The windows are closed, so there is no connection with the outside air.

Answer
Because of buoyancy, the helium balloon on the string will want to move in the direction opposite the effective gravitational field existing in the car. Thus, when the car turns the corner, the balloon will deflect towards the inside of the turn.