课程名称︰普通物理学乙 课程性质︰必修 课程教师︰朱士维 开课学院：医学院 开课系所︰医学系 考试日期（年月日）︰2011/11/9 考试时限（分钟）：180分钟 是否需发放奖励金：是，感谢:) （如未明确表示，则不予发放） 试题 : 1.(10%)During our entire lifetime,interactions with various people are inevitable. It is vital to show mutual respect in these interactions. One of the key components in successful interaction/communication is to know others' names. So, please write down the names of our teaching assistants in this General Physics course(in Chinese or English, be sure you spell correctly). 2.(10%)(Order of magnitude estimation) The larger storage capacity of a blu-ray disc compared to DVD(digital video disk) and CD(compact disk) is achieved through smaller focal spot size. Assuming all discs have the same active areas, which are capable of being written in, with an outer diameter of 12cm and an inner diameter of 4cm. Please give an order of magnitude estimation of the capacity of CD, DVD, and blu-ray disc, respectively. (1 pit can store 1 bit of data and 8 bits composes 1 byte) (图示:1 pit 的个别尺寸(diameter): CD-2.11μm DVD-1.32μm Blu-ray-0.58μm) 3.(5%)There are three classes of levers, as shown in the figure. Which one is suitable to describe our back when you bend forward to lift a weight? (课本图: http://i.imgur.com/RRuLg.jpg) 4.(5%)An object is held in place by friction on an inclined surface. The angle of inclination is increased until the object starts moving. If the surface is kept at this angle, the object A. slows down B. moves at uniform speed C. speeds up D. none of the above Please explain explicitly the reason of your selection. 5.(5%)Consider the object on the inclined plane(angleθ);f is the frictional force acting on it by the plane, N the normal force exerted on it due to the plane,and W the weight of the object. If the object is stationary, which of the following statements are true? A. f=μN B. f=Wsinθ C. N=Wcosθ D. none of the above Please explain explicitly the reason of your selection. 6.(10%)Michael Jordan, the greatest basketball player of all time, is famous of performing slam dunks from the free throw line. Given that the distance of the basket to the free throw line d=4.225m, the height of the basket H=3.05m, and assuming the ball height is also h=3.05m in Jordan's raised hand, please determine (a)(5%)the minimal initial velocity at the free throw line required for Jordan to perform slam dunk(Assuming he keeps his body rigid and assuming the jump-off angle is 45 degree); (b)(5%)If he is 100-kgw how much force should be applied by his leg to achieve this jump? What is the direction of this force? 7.(5%)Calculate the terminal velocity of a 1-cm bug. Assume that the density of bug is 1g/cm^3 and that the bug is spherical in shape with a diameter of 1cm. Assume further that the area of the bug subject to air friction is πr^2. The coefficient of air friction is 0.88kg/m^3 8.(10%)The speed of F1 racing car is 360km/h. If the friction coefficient is 1.5 between the tires and track, how much angle the track should be banked to allow the car to turn through a curve with 50-m radius? Neglecting air drag here. 9.(10%)(a)Define yield and rupture strength. (b)Please plot a typical stress- strain curve and identify the points of yield and rupture strength on the curve. 10.(10%)(bonus)When two atoms form a molecule, such as O2, through chemical bonding, the potential energy of the resultant molecular bond is called Morse potential. Morse potential is a function of atom separation, V(x)=Vo[1-exp(-x/δ)]^2-Vo. Knowing that the molecular force is equal to F=-dV/dx, please find out the natural oscillation frequency when the displacement x is small. 11.(10%)A 60-kgw person is performing fast-spin during ice-skating. He starts from slow-spin during ice-skating. He starts from slow-spin with stretched arms, and speeds up when he raises his arms. (a)(5%)Assuming the person can be modeled as two cylinders. During"stretched arms" posture, the radius, length and mass of the horizontal cylinder(the arms)are 10cm, 200cm, and 15 kg respectively. The radius and length of the vertical cylinder is 40cm and 160cm, respectively. While in the "raised arms" posture, the radius, length and mass of the upper cylinder(the arms)are 10cm, 80cm, and 15kg, respectively. Based on the table given below, what are the moments of inertia of the performer with stretched arms and raised arms, respectively? (b)(5%)The speed of slow-spin is 1rev/sec. What is the spin speed when the performer raises his arms?(附有转动惯量表) 12.(5%)Which kind of coin is easier to float on water? A. 1NTD B. 5NTD C. 10NTD D. 50NTD Assuming that all coins are made of the same material. Please explain your answer in detail. 13.(5%)We have mentioned in class that Bernoulli's equation can be derived from Navier-Stokes equation with 4 assumptions, one of which is "incompressible flow". Nevertheless, air is "compressible", so is it okay to use Bernoulli's equation to explain fluid dynamics of air? 14.(5%)What is the main difference between Poiseuille's and Bernoulli's law? 15.(5%)How much is the average energy consumption of human body through radiation per day?(assuming the emissivity of our body is 1; the value of Boltzmann constant is 5.67 x 10^-8 W/m^2-K^4; make other necessary assumptions by yourself) --

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