北航2012年秋《大学物理(上)》在线作业三(国外英文资料).doc

北航2012年秋《大学物理(上)》在线作业三(国外英文资料) Northern University Physics (on) online homework three I. radio questions 1. under the following circumstances, the simple pendulum can make the vibration period of harmonic motion smaller A. reduces the amplitude of the pendulum to half its original amplitude B. moved the pendulum from the flat to the high mountains C. moves the pendulum from the equator to the poles D. uses a funnel filled with sand to make a pendulum, which lets the sand leak out during the oscillation The correct answer: D 2. which of the following statements is true for objects moving along a curve? A. the tangential acceleration must not be zero The normal acceleration of the B. must not be zero (except at the inflection point) C. because the velocity is in the tangential direction, the normal velocity must be zero, so the normal acceleration must be zero. D. if the body moves at a uniform rate, the total acceleration will be zero. The correct answer: B 3., according to Maxwells law of molecular velocity distribution, the molecules with the most probable rate (the most probable rate) VP are kinetic energy [[]] A. 1/2kT B. 3/2kT C. kT D. 3/2RT The correct answer: C 4. in the following statement of rigid body motion, what is wrong is... A. translation and rotation are the basic motions of rigid bodies In any rigid body on a rigid body, the motion of a rigid body remains parallel at the same time, while the motion of the rigid body is parallel to the motion of the rigid body of the B. All the points on a rigid body of a C. move in a circular motion around the same line, which is called the rotation of a rigid body When the rigid body of a D. rotates, each point of a rigid body has the same speed and acceleration The correct answer: D 5. the following is true about the reference system The A. reference system is an object chosen as a standard abstracted from the relativity of motion The B. reference frame is stationary C. selects different reference frames, and the m