西安交大考试卷(理论力学英文)

课程名称 理论力学A1（英） 2003 —2004学年第 1 学期 学 号 开 课 系 工程力学系 年级 本科二年级 姓 名 任课老师 柳葆生 评分 规定：仅允许携带电子词典、计算器和教师提供的课程总结

1. Member BD exerts on member ABC a force P directed along line BD.

Knowing that P must have a 360-N vertical component, determine (a) the

magnitude of the force P, (b) its horizontal component. (零件BD 对零件

ABC 沿BD 线施加一个力P ，已知P 的垂直分量为360-N ，计算（a ）

力P 的大小，（b ）力P 的水平分量

)

2. Two forces P and Q are applied as shown to an aircraft connection. Knowing that the connection is in equilibrium and that P = 250 N and Q = 325 N, determined the magnitude of the forces exerted on the rods A and B. (如图所示，两个力P 和Q 施加于一个飞机连接器。已知连接器处于平衡状态，并且P = 250 N 和Q = 325 N ，确定施加于连杆A 和B 上力的大小)

3. A 150 N force, acting in a vertical plane parallel to the yz plane, is

applied to the 200 mm long horizontal handle AB of a socket wrench.

Replace the force with a equivalent force-couple system at the origin O

of the coordinate system. (一个150 N 的力，作用在平行于yz 平面的

垂直平面内，施加于一个套筒扳手200 mm 长的水平手柄上。用一个

在坐标原点O 的等效力－力偶系统代替这一力

)

4. Knowing that the tension in wire BD is 1500 N, determine the

reaction at the fixed support C of the frame shown. (已知拉索BD 中

的张力为1500 N ，确定如图示在框架固定支撑端C 的约束反力)

5. Determine the forces in each member of the truss shown. State whether

each member is in tension or compression. (确定图示桁架中每个杆件中的

力。说明每个杆件受拉力或压缩力)

6. A uniform crate of mass 30 kg must be moved up along the 15º

incline without tipping. Knowing that the force P is horizontal,

determine (a) the largest allowable coefficient of static friction between

the crate and the incline, (b) the corresponding magnitude of the force P.

(一个匀质的30 kg 货箱必须被沿15º斜面上移，并不发生倾翻。已

知力P 为水平方向，确定：

（a ）在货箱和斜面间所允许的最大静摩擦系数，（b ）相对应力P 的大小)

7. The acceleration of a point P moving in a plane is given by j )5t 4(i t 3a 2r r r ++=2s /m , where t is the time in seconds. When t = 2, the position and velocity are respectively )j 33.26i 12(r r +m and j 21i 10r r +s /m . Determine the position and velocity at t = 1. (点P 在平面中移动，其加速度表达式为j )5t 4(i t 3a 2r r r ++=2s /m ，其中t 为以秒为单位的时间。当t = 2, 其位移和速度分别为)j 33.26i 12(r r +m 和 j 21i 10r r +s /m ，确定t = 1时的位移和速度)

8. A car leaves a motorway at point A with a speed of 100

km/h and slows down at a uniform rate. Five seconds later,

as it passes B, its speed is 50 km/h (see Figure). The radius

of curvature of the exit road at B is 110 m. The mass of the

car is 1500 kg. Find (a) the acceleration of the car at B and

(b) the total force exerted by the car on the road at B. (一辆

轿车在点A 以100 km/h 的速度离开高速公路，并均匀减

速。5秒钟后，通过B 时，其速度为50 km/h （见图）。求

出（a ）轿车在B 点的加速度，（b ）在B 点轿车对地面所

施加的总力)