You are driving your niece to a birthday party, and she is bringing a floating balloon filled with helium. When you make a sharp left turn, you both shift to the right. Which way does the balloon shift? Assume the windows are closed.
The balloon sways to the left, unlike you and your niece. This is because:
- Inertia causes everything in the car to move to the right (relative to the car) when the car turns left.
- The helium-filled balloon is lighter than the air around it, so the air has greater inertia. So the all the air shifts to the right and displaces the balloon to the left.