13上期中双语物理试卷 - 图文

…… …名 … 试姓卷装订线 …… ………… 装号订 线学内不要答题 ，不要填 写级考班生业信专息………… ……试卷 装院订学线 ………… 武汉理工大学考试试卷（期中卷） 2012 ~2013 学年 2 学期 大学物理C（双语） 课程 闭卷 时间120分钟，72 学时，4.5学分，总分100分，占总评成绩70% 2013年5月6日 题号 一 二 三 四 五 六 七 八 九 十 合计 满分 18 18 64 100 得分 得分 一、选择题(本题共18分，每小题3分) 1. A particle of mass m, initially at rest, is accelerated by a force that increases in time as F = Ct2, where C is a constant. Determine its position x as a function of time and the work W by the force from t=0 to t=t. Ans:( ) A.x?Ct42Ct4412m,W?Ct618m; B.x?12m,W?C2t66m; C.x?Ct4C2t63m,W?12m; D.x?Ct,2W?Ct63m 2. The electric potential at points in an xy plane is given by V= 2x2–3y2 ( V/m2). The electric fieldE?at point P ( 3m, 2m ) is Ans:( ) A.E???12?i?12?j(V/m); B.E??12?i?12?j( V/m); C.E???6?i?6?j( V/m);D.E??6?i?6?j( V/m) 3. A point charge q is placed at one corner of the cube of edge l, as in Fig.1-1. The total flux through the cube faces is Ans:( ) A. q?; B. q; C. q ; D. q.04?08?6? Fig.1-1 004. In Fig.1-2, a rod of length L has charge -q uniformly distributed along its length. Take V=0 at r = ∞, the electric potential V at point P is Ans:( ). A.q; B.?q; C.?q4??lnL?a; D.qlnL?a. 4??0(L?a)0a4??0La4??0LaFig. 1-2 5. Fig.1-3 shows a wire of arbitrary shape carrying a current I between point awire in a plane at right angle to a uniform magnetic field B. y and b. The B?Then the magnitude of the force on the wire is Ans:( ). Fig.1-3 A. 0; B. ILB?i; C. ?ILB?j; D. ILB?j. IaLb6. What is the speed of a particle whose kinetic energy is equal to twice of its rest energy? x A. 1c; B. 222 33c; C. 3c; D. 23c. Ans:( ) 得分 二、填空题(本题共18分，每空2分) 1. A body moves in a circle of radius 3m with its speed given by v =3t－t3, with υ in meters per second and t in seconds, At t =2s, the tangential acceleration at = . 2. A satellite(卫星) of mass m moves in a circular orbit of radius r around a planet of mass M. The potential energy U of the system is . i b 3. In Fig.2-1, a wire is formed into a closed circuit with radii a and b, and a carries a current i. The magnetic dipole moment(磁矩)of the circuit is . C Fig.2-1 1

4. In Fig.2-2, a parallel-plate capacitor has plates of area A and separation d and has charges +Q and –Q. If a large metal sheet of thickness b is placed between, and parallel to the capacitor, now the net capacitance C= , and Fig. 2-2 the stored energies U= . 5. The principles of the special theory relativity are and . 6. Figure 2-3 shows four identical currents i, and two Amperian paths encircling them. ????BBFind ? (a ) ?d l ? ; ?( b ? d l ? . )Fig. 2-3 得分 得分 三、计算题(本题共64分) 1.(12') In Fig.3-1, a thin rod of mass M and length l is suspended vertically from a frictionless pivot O at its upper end. A mass m of putty(泥块) traveling horizontally with a speed v strikes the rod at its bottom and sticks(粘住) there. O(a) What is the angular velocity ω of the rod just after the putty strikes rod? (b) How high H does the bottom of the rod swing? MC C HAA Fig. 3-1 2

得分 2. (12')Figure 3-2 shows two blocks, m1 and m2 , which are connected by a massless cord that passes over a pulley (no slip), and the pulley has radius R and moment of inertia I abut its axle. (a) Draw free-body diagrams(受力图), for each of the two blocks and the pulley(滑轮). (b) Determine the acceleration a of the blocks m1 and m2 (m1 < m2). mOR?am1a Fig. 3-2 3.(14') In Fig.3-3, a spherical conducting shell (导体壳)，of inner radius r1 and outer 得分 m2 r0, carries a net charge Q and there is a point negative charge -q at its center C. (a) What are the charges on the inner and outer surfaces of the shell? (b) Find the electric field E, as a function of the radius r (0 R2. (b) Calculation the energy U stored in the magnetic field for a length outer cylinder providing the return path for that current . 4.(14’) Fig.3-4 shows a long coaxial cable, which consists of two ……between R1and R2 is2πr… …The flux through the differential 试 ??卷area dAis dΦ?B?dA?Bldr 装订R2?0I 线Φ?dΦ?ldrR12πr …The inductance is… ?0lR2Φ…L??lnR… 2Fig.3-4 I2πR1…… 装订 线 内5. (12') A circular conducting ring of R is connected two exterior straight 不得分 要wires ending at two ends of diameter (Fig.3-5). The current I splits into 答题unequal portions with passing through the ring as shown. ，(a) What is the magnetic field B at point C ? 不要??(b) If the current wires are placed in uniform magnetic fieldB0?B0i, find the net force on 填写?考the wires. B0 生 信息 … …… … …… 试Fig.3-5 卷装订线…………l of the cable. The magnetic field B??0IR1IIrl?? 4

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