Some physics questions I don't know the answer to: 1) An old Car Talk puzzle of the week is about a truck carrying a load of chickens. As it approaches a mandatory truck scale, the driver realizes that its weight is just over the legal limit. To lighten the truck, he or she makes a loud noise, frightening the chickens so that they fly into the air just in time for the truck to be weighed. Question: Does this succeed in lightening the load? 1a) Also, does it matter whether the truck is airtight or open? ----- 2) In a related question, people on a sailboat realize that it needs to get back to shore in a hurry, so they attach a powerful fan to a powerful battery and aim it at the sail. Can this help propel the boat? 2a) Likewise, suppose this picture is scaled down to become a small toy boat. Does it matter if all takes place in an airtight enclosed case? ----- —Dan