※ [本文转录自 NTU-Exam 看板] 作者: leews () 看板: NTU-Exam 标题: [试题] 94下 蔡尔成 普物乙 期中考 时间: Wed Apr 26 18:19:15 2006 课程名称︰普通物理乙 课程性质︰ 课程教师︰蔡尔成 开课系所︰职治 考试时间︰95.4.26 试题 : 1.[10%](a)[5%]What is "work-energy"theorem? 何谓"work-energy"定律? (b)[5%]What is "conservative force field"?何谓保守力场? 2.[10%]Deduce Kepler's third law from Newton's universal law of gravity. i.e.,show that T^2/r^3 is the same for any two planets about the sun. Assuming the orbit of any planet is a circle with radius r. 由万有引力定律， 导出星球运动T^2/r^3 对每星球皆相同，假设星球轨道为半径r的圆。 3.[10%]Our lungs contain hundreds of millions of alveoli. Explain how and why we may exhale without muscle action with the help of these alveoli. 人体有上 亿肺泡，解释为何这些肺泡可使人类呼气而不须肌肉动作。 4.[10%]For an ice skater spinning on the tip of her skate with her arms extended initially, explain why her rate of spin increases when she pulls in her arms. 一个溜冰者开始旋转时手臂伸出，解释为何手臂往内收缩时旋转加速 5.[10%]Assume the initial speed of one mass is v and the initial speed of 1 the other mass is zero.(a)Prove that for a collision of equal masses, 1/2mv^2=1/2mv'^2+1/2mv'^2+mv'v'cosθ where θ is the angle between the 1 1 2 1 2 velocities of the two masses after collision, and the final speeds after collision are v' and v'. 1 2 (b)Show θ is a right angle if the aforementioned collision is elastic. 6.[10%]The moment of inertia of a long rod spun about an axis through one end perpendicular to its length is ML^2/3.Why is this greater than it would be if you spun a point mass M at the location at the center of mass of the rod(at L/2)? 7.[10%]What is the final velocity of a hoop that rolls without slipping down a hill of height h, starting from rest? 8.[10%]The flow rate of blood in a coronary artery has been reduced to half its normal value by plaque deposits. By what factor has the radius of the artery been reduced, assuming no turbulence occurs?given (1/2)^1/2=0.707,(1/2)^1/3=0.794,(1/2)^1/4=0.841,(1/2)^1/5=0.871, (1/2)^1/6=0.891 9.[10%]When water freezes,its volume increases by 9.05%(i.e.,ΔV/V=9.05*10^-2) What force per unit area is water capable of exerting on a container when it freezes?The Bulk modus for water is 2.2*10^9 N/m^2. 10.[10%]Write down the Bernoulli's equation in Fluid Dynamics. For every variable in this equation, you need to explain what the corresponding physical quantity is. For example,we may have g in this equation and then you need to say that g is the acceleration of gravity.(But you do not need to derive this equation.)写下Bernoulli's equation且说明方程式内每一变数含意 --

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