华东理工大学2014-2015年大学物理双语期中考试题

2t
D.2t
E. t / 2
upper string
lower string
3.A heavy ball is suspended as shown. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The first result occurs because: A. the force is too small to move the ball; B. the ball has inertia; C. action and reaction is operating D. air friction holds the ball back E. the ball has too much energy
13.The displacement of an object oscillating on a spring is given by x(t) = Acos(ωt + φ). If the object is initially displaced in the negative x direction and given a negative initial velocity,then the phase constant φ is between: A. 0 and π/2 rad; B. π/2 and π rad; C. π and 3π/2 rad; E. none of the above (φ is exactly 0, π/2, π, or 3π/2 rad) D. 3π/2 and 2π rad
A. 1/9 the KE of block B. B. 1/3 the KE of block B. C. 3 times the KE of block B. D. 9 times the KE of block B. E. the same as the KE of block B. 15. a mass of 2 kg is attached to three springs of spring constants 1 N/m, When the mass is at rest the springs are unstretched. For this system: A. 2 0.5rad / s 2 ; E. 2 1rad / s 2 B. 2 2rad / s 2 ; C. 2 1.5rad / s 2 ; D. 2 3rad / s 2 ; and
A P ath 1 P ath 2 B
Which of the following five graphs correctly gives the force F exerted on the particle?
12.A small object of mass m, on the end of a light cord, is held horizontally at a distance r from a fixed support as shown. The object is then released. What is the tension in the cord when the object is at the lowest point of its swing? A. mg/2; B. mg; C. 3mg/2; D. 2mg; E. 3mg
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4.. Two particles of equal mass undergo a two dimensional elastic collision (not head on), the target particle being initially at rest. The angle between the velocity vectors of the two particles after the collision is:
A. less than 90° B. greater than 90° C. equal to 90°D. depends on the speed of the incident particle E. cannot be predicted
5. A particle starts from rest and is acted on by a net force that does work at a rate that is proportional to the time t. The speed of the particle is proportional to: (A) 1 / t (B) t (C) t 2 (D)
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distance from the center of Earth that the projectile will reach is: A.5R/4; B.4R/3; C.3R/2; D.2R;
E.4R
10.A particle begins with kinetic energy K1 at point A. It moves along path 1 to point B, then along path 2 back to point A. It ends with kinetic energy K2 where K2 > K1. Which statement below can one correctly conclude? A. The net force on the particle was always centripetal. B. The potential energy of the system decreased. C. At least one non-conservative force acted on the particle. D. The kinetic energy of the particle at point B is > K1 and < K2. 11. The graph below shows the potential energy U for a particle moving on the x axis.
the tension in wire A is closest to: A.245N; B.280N; C.87.5N; D.517N; E.333N
7.The sketch below shows a block of mass m on an inclined plane that makes an angle with the horizontal direction. The block is being held stationary by the force of static friction between the block and the plane. The coefficient of static friction between the block and the plane is us. The magnitude of the net force exerted on the block is: A. usmg cos D. mg cos B. usmg sin E. mg sin C. zero 8. The pilot of a light airplane with an airspeed of 200 km/h wants to fly due west. There is a strong wind of 120 km/h blowing from the north.If the pilot points the nose of the airplane north of west so that her ground track is due west, what will be her groundspeed? A. 160 km/h. B. 120 km/h C. 80 km/h D. 180 km/h E. It would impossible to fly due west in this situation 9. A projectile is fired straight upward from Earth’s surface with a speed that is half the escape speed. If R is the radius of Earth, and air resistance is ignored, the greatest
2t
2.Two identical stones are dropped from rest and feel no air resistance as they fall. Stone A is dropped from height h, and stone B is dropped from height 2h. If stone A takes time t to reach the ground, stone B will take time: A. t/2 B. 4t C.
华东理工大学 2014–2015 学年第二学期
《大学物理》双语课程期中考试试卷
开课学院：理学院
2015.4
120 分钟
专业：中德环境/电子 ቤተ መጻሕፍቲ ባይዱ试形式：闭卷，所需时间
考生姓名：
学号：
班级
Part C
任课教师 谢海芬
题序
Part A
Part B 1 2 3
总 分
得分 评卷人
Part A. (45points) Each question is worth 3points. Write the letter corresponding to the best answer to the question to the answer sheet below. 1.An object moves in a circle of radius R at constant speed with a period t. If you want to change only the period in order to cut the object's acceleration in half, the new period should be: A. 4t B. t/2 C. 2t D. t / 2 E
t （E)) 1/t
6.Three objects are connected by massless wires over a massless frictionless pulley as shown in Fig. . The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N.
14.Block A on the left has mass 1.00 kg. Block B on the right has mass 3.00 kg. The
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blocks are forced together, compressing the spring. Then the system is released from rest on a level, frictionless surface. After the blocks are released, the kinetic energy (KE) of block A is