课程名称︰普通物理乙 课程性质︰必修 课程教师︰王建万 开课学院： 开课系所︰农化系 考试日期（年月日）︰2012.1.11 考试时限（分钟）：120分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. What are (a)speed and (b) the period of a 280kg satellite in an approximately circular orbit 720km above the surface of Earth? Suppose the satellite loses mecjanical energy at the average rate of 1.8x10^5 J per revolution. A dapting the reasonable approximation that the satellite's orbit become a "circle of slowly diminiching radius, "determine the satellite's (c) altitude, (d) speed, and (e) period at the end of ots 2500 revolution. (f) What is the magnitude of the average retarding force on the satellite? Is angular momentum around Earth's center conserved for (g) the satellite and (h) the satellite-Earth system (assuming that system is isolated and that Earth's radius R=6370km) ? 2. An oscillator consists of a block of mass 0.800kg connected to a spring. When set into oscillation with amplitude 60.0cm , the oscillator repeats its motion every 0.250s. Find the (a) period, (b) frequency, (c) angular frequency, (d) spring constant, (e) maximum speed, and (f) magnitude of the maximum force on the block from the spring, 3. A girl is sitting mear the open window of a train that is moving at a velocity of 30.00 m/s to the east . The dirl's uncle stands near the tracks and waches the train move away. The locomotive whistle emits sound at frequency 720.0 Hz . The air is still . (a) What frequency does the uncle hear? (b) What frequency does the girl hear? A wind begins to blow from the east at 20.00m/s . (c) What frequency does the girl now hear? (d) What freqency does the uncle now hear ? In the cases of (c) and (d) , what is the sound speed with respect to (e) the uncle, and (f) the girl? 4. A bowler throws a bowling ball of radius R=11.0cm along a lane. The ball (Fig.1) (Holiday第九版 Fig.11-38) slides on the lane with initial speed Vcom,o=12.0m/s and initial angular speed ωo=0. The coefficient of kinetic friction between the ball and the lane is 0.320. The kinetic friction force fk acting on the ball causes a linear acceleration of the ball while producing an angular acceleration of the ball. When speed Vcom has decreaced enough, the ball stops sliding and then rolls smoothly. (a) What then is Vcom in terms of ω? During the sliding, What are the ball's (b) linear aceleration and (c) angylar acceleration? (d) How long does the ball slide? (e) How far does the ball slide? (f) What is the linear speed of the ball when smooth rolling begins? 5. In Fig.2 (课本Fig.12-46), the drver of a car on a horizontal road makes an emergency stop by applying the brakes so that all four wheels lock and skid along the road. The coefficient of kinetic friction between tires and road is 0.320. The separation between the front and rear axles is L=4.80m, and the center of mass of the car is located at distance d=2.20m behind the front axle and distance 0.750m above the road. The car weighs 15.0 kN. Find the magnitude of (a) the braking acceleration of the car, (b) the normal force on each rear tire, (c) the normal force on each front wheel, (d) the braking force on each rear wheel, and (e) the braking force on each front wheel. 6. Fig.3 (课本Fig.14-54) shows a stream of water flowing through a hole at depth h=16.0cm in a tank holding water to height H=60.0cm. (a)At what distance x does the stream strike the floor? (b) At what depth should a second hole be made to give the same valur of x? (c) At what depth should a hole be made to maximize x? If another hole is made at depth h giving to x=40.0cm, what are (d) the speed of the water stream at the outlet of the hole, and (e) the time needed for the stream strikes the floor? 7. A sinusoidal transverse wave of wavelength 24.0cm travels along a string in the positive direction of an x axis. The displacement y of the string particle at x=0 is given in Fig.4 (课本Fig.16-33) as a fuction of time t. The scale of the vertical axis is set by ys=6.00cm. The wave equation is to be in the form y(x,t)=ym sin(kx±ωt+ψ). (a) At t=0, is a plot of y versus x in the shape of a positive sine function of a negative sine function? What are (b) ym, (c) k, (d) ω, (e) ψ, (f) the sign in front of ω, and (g) the speed of the wave? (h) What is the transverse velocity of the particle at x=0 when t=5.00s? 8. When a system is taken from state f along path iaf in Fig.5 (课本Fig.18-39) Q=80.0cal and W=32.0cal. Along path ibf, Q=54.0cal. (a) What is W along path ibf? (b) If W=-19.5cal for the return path fi, what is Q for (d) path ib and (e) path bf? (f) what is the temperature Ti in Kelvin at state i if the system contains one mole of ideal He gas (assuming that constent volume molar specific heat Cv= (3/2)R, ideal gas constant R=8.31J/mol-K)? --

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