airplane conveyors
thank fsm for mythbusters. if you put an airplane on a conveyor belt running at the airplane's take off speed in the opposite direction... can the airplane take off? cecil adams of the straight dope fame had all kinds of trouble with
this one. if you've never heard of mythbusters it's a great tv show. they put popular myths to the test. in this case they put a full scale airplane on a conveyor belt. and guess what! it took off. just like cecil said. but lotta folks didn't believe him. the problem is there's some ambiguity in the question. i phrased it above without ambiguity. usually the question is posed using the phrase "speed of the airplane" instead of "take off speed". most people have never flown an airplane. but they have driven cars. so they naturally think speed means wheel speed. and by that definition, if the airplane's wheel speed matches the conveyor belt's speed then the plane isn't going anywhere. but it's not because of some magical mystical non-existent force holding the plane in place. it's because when you untie the plane and let it move itself its wheel speed will no longer match the conveyor speed. the wheel speed is the conveyor speed plus the airplane's ground speed. whew. glad we got that taken care of. thanks adam and jamie!