Question: A semi truck is driving down the highway but the driver isn't paying attention. He goes under an overpass that is too short for his truck by only inches and gets stuck. He thinks it's going to be a very costly mistake but one of his friends happens to pass by and explains to him how he can get out in the matter of minutes without any help.
What does he suggest?
Answer: He suggests that he let air out of his tires to make it short enough to back out of the overpass.
Question: You are in a car with some helium balloons and hit the gas. While you accelerate, which way does the balloon move?
Answer: It moves forward towards the front of the car, even though you are forced backwards. The helium balloon is less dense than the air so when you accelerate the air in the car will move backwards compared to the balloon pushing the balloon forward because the balloon is lighter.