※ [本文转录自 NTU-Exam 看板] 作者: PTIC (patrick) 看板: NTU-Exam 标题: [试题] 95上 王建万 普通物理学甲上 期中考 时间: Tue Jan 23 19:01:21 2007 课程名称︰普通物理学甲上 课程性质︰共同必修 课程教师︰王建万 开课学院： 开课系所︰生工系 考试日期（年月日）︰2006/11/17 考试时限（分钟）：110 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : Mid Term Exam 1.A force F=(3.00N)i+(7.00N)j+(7.00N)k acts on a 2.00kg mobile object that moves from an initial position of di=(3.00m)i-(2.00m)j+(5.00m)k to a final position of df=-(5.00m)i+(4.00m)j+(7.00m)k in 4.00s. Find (a) the work done on the object by the force in the 4.00s interval, (b) the average power due to the force during that interval, and (c) the angle between vectors di and df. (10%) 2.A collision occurs between a 2.00kg particle traveling with velocity v1= (-4.00m/s)i+(-5.00m/s)j and a 4.00kg particle with velocity v2=(6.00 m/s)i+(-2.00m/s)j. The collision connects the two particles. What then is their velocity in (a) unit-vector notation and as a (b) magntitude and (c) angle? (10%) 3.In Fig.1, a 1.40kg ball is connected by means of two massless strings, each of the length 1.70m, to a vertical, rotating rod. The strings are tied to the rod with separation d=1.80m and are taut. The tension in the upper string is 40N. What are (a) the tension in the lower string, (b) the magntitude of the net string force Fnet.str on the ball, and (c) the speed of the ball? (d) What is the direction of Fnet.str? (13%) 4.An elevator cab of mass 500kg is descending with the speed vi=4.0m/s when its supporting cable begins to slip, allowing it to fall with constant acceleration a=g/5 (Fig.2). (a) During the ball through a distance d=12m, what is the work Wg done on the cab by the gravitational force Fg? (b) During the 12m fall, what is the work Wt done on the cab by the upward pull T of the elevator cable? (c) What is the net work W done on the cab during the fall? (d) What is the cab's kinetic energy at the end of the 12m fall? (13%) 5.In Fig.3, a baseball is hit at a height h=1.00m and then caught at the same height. It travels alongside a wall, moving up past the top of the wall 1.00s after it is hit and then down past to the top of the wall 4.00s later, at distance D=50.0m farther along the wall. (a) What horizontal distance is traveled by the ball from hit to catch? what are the (b) magntitude and (c) angle (relative to the horizontal) of the ball's velocity just after being hit? (d) How high is the ball? (13%) 6.In Fig.4, a chain consisting of five links, each of mass 0.100kg, is lifted vertically with constant acceleration of magntitude a=2.50m/s^2. Find the magntitude of (a) the force on link1 from link2, (b) the force on link2 form link3, (c) the force on link3 from link4, and (d) the force on link4 from limk5. Then find the magntitudes of (e) the force F on the top link from the person lifting the chain and (f) the net force accelerating each link. (16%) 7.In Fig.5. a 3.5kg block is accelerated from rest by a compressed spring of spring constant 640N/m. The block leaves the spring at spring's relaxed length and then travels over a horizontal floor with a coefficient of kinetic friction μk=0.25. The friction force stops the block in a distance D=7.8m. What are (a) the increase in the thermal energy of the block-floor system, (b) the maximum kinetic energy of the block, and (c) the original compression distance of the spring? (10%) 8.In Fig.6, one block has mass M=500g, the other has mass m=460g, and the pulley, which is mounted in horizontal frictionless bearings, has a radius of 5.00cm. When released from rest, the more massive block falls 75.0cm in 5.00s (without the cord slipping on the pulley). (a) What is the magntitude of the blocks' acceleration? What is the tension in the part of the cord that supports (b) the more massive block and (c) the less massive block? (d) What is the magntitude of the pulley's angular acceleration? (e) What is its rotational inertia? (15%) Fig.1在普物课本第七版p.135 Fig.6-42 Fig.2我找不到 Fig.3:p79 Fig.4-42 Fig.4:p110 Fig.5-43 Fig.5:p193 Fig.8-51 Fig.6:p268 Fig.10-44 -- 一张好人卡可以换多少p币啊 --

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