北航12春《大学物理(上)》在线作业一(国外英文资料).doc

北航12春《大学物理(上)》在线作业一(国外英文资料) 1-5:DBBBA 6-10:ABCCD 11-15:CDACA Radio First, radio questions (15 questions, 60 points) V 1. (D) See pictures for questions A. B. C. D. Full marks: 4 2. which of the following statements is true (B) 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. Full marks: 4 The 3. vessel contains 11 kg carbon dioxide and 2 kg hydrogen gas (two gases are regarded as ideal gases for rigid molecules). The internal energy of the known mixture is 8.1 * 106 J., and the temperature of the mixed gas (B) is A. 273, K B. 300, K C. 373, K D. 400, K Full marks: 4 4. a planet leaves the earth at a speed of V, and its spectrum appears on the earth, [B] A. spectra remain unchanged B. spectral redshift C. spectrum purple shift D. spectral compression Full marks: 4 5. ideal heat source temperature is 800K, if the efficiency is 40%, then the temperature of the heat source is about [A]K. A. 480 B. 484 C. 961 D. 589 Full marks: 4 6. in the process of harmonic wave propagation, the velocity of vibration is [A (1/2) at two points away from the propagation direction The A. is the same size, but the opposite direction B. size and direction are the same C. of different sizes, the same direction The D. is different in size, but in the opposite direction Full marks: 4 There is a passenger in the 7. car standing upright and still falling back. What kind of movement does the train do? [B] A. turn B. uniform rectilinear motion C. accelerates rectilinear motion D. deceleration linear motion Full marks: 4 See the picture for 8. questions (C) A. B. C. D. Full marks: 4 9. man-made earth satellites orbit the earth in elliptical orbits. Satellite orbits, perigee and a