Simple Nature - Light and Matter

Page 810, problem 60: Expand sin θ in a Taylor series around θ = 90 ◦ .Answers to Self-ChecksAnswers to Self-Checks for Chapter 0Page 15: If only he has the special powers, then his results can never be reproduced.Page 17: They would have had to weigh the rays, or check for a loss of weight in the objectfrom which they were have emitted. (For technical reasons, this was not a measurement theycould actually do, hence the opportunity for disagreement.)Page 25: A dictionary might define “strong” as “possessing powerful muscles,” but that’s notan operational definition, because it doesn’t say how to measure strength numerically. Onepossible operational definition would be the number of pounds a person can bench press.Page 28: A microsecond is 1000 times longer than a nanosecond, so it would seem like 1000seconds, or about 20 minutes.Page 29: Exponents have to do with multiplication, not addition. The first line should be 100times longer than the second, not just twice as long.Page 32: The various estimates differ by 5 to 10 million. The CIA’s estimate includes aridiculous number of gratuitous significant figures. Does the CIA understand that every day,people in are born in, die in, immigrate to, and emigrate from Nigeria?Page 33: (1) 4; (2) 2; (3) 2Page 35: 1 yd 2 × (3 ft/1 yd) 2 = 9 ft 21 yd 3 × (3 ft/1 yd) 3 = 27 ft 3Page 41: C 1 /C 2 = (w 1 /w 2 ) 4Answers to Self-Checks for Chapter 1Page 58: The stream has to spread out. When the velocity becomes zero, it seems like thecross-sectional area has to become infinite. In reality, this is the point where the water turnsaround and comes back down. The infinity isn’t real; it occurs mathematically because we useda simplified model of the the stream of water, assuming, for instance, that the water’s velocityis always straight up.Page 60: A positive ∆x means the object is moving in the same direction as the positive xaxis. A negative ∆x means it’s going the opposite direction.Page 66: (1) The effect only occurs during blastoff, when their velocity is changing. Once therocket engines stop firing, their velocity stops changing, and they no longer feel any effect. (2)It is only an observable effect of your motion relative to the air.Page 68: Galilean relativity says that experiments can’t come out differently just becausethey’re performed while in motion. The tilting of the surface tells us the train is accelerating,but it doesn’t tell us anything about the train’s velocity at that instant. The person in the trainmight say the bottle’s velocity was zero (but changing), whereas a person working in a referenceframe attached to the dirt outside says it’s moving; they don’t agree on velocities. They doagree on accelerations. The person in the train has to agree that the train is accelerating, sinceotherwise there’s no reason for the funny tilting effect.Page 69: Yes. In U.S. currency, for instance, the quantum of money is one cent.921