9. An engine does 15 kJ of work while exhausting 37 kJ to a cold reservoir. What is the efficiency of the engine? (A) 28.8 % (B) 38.8 % (C) 68.8 % (D) 88.8 % (E) 98.8 %

6. The figure shows four situations in which a source of sound S and a detector D are either moving or stationary. The arrows indicate the directions of motion. The speeds (when not zero) are all the same. (Note that the detector in situation ③ is stationary). Rank the situations according to the apparent frequency of the source, lowest to highest. (A) ①,②,③,④ (B) ④,③,②,① (C) ①,③,②,④ (D) ②,①,④,③ (E) ②,①,③,④

9. An engine does 15 kJ of work while exhausting 37 kJ to a cold reservoir. What is the efficiency of the engine? (A) 28.8 % (B) 38.8 % (C) 68.8 % (D) 88.8 % (E) 98.8 %

其他試題

9. An engine does 15 kJ of work while exhausting 37 kJ to a cold reservoir. What is the efficiency of the engine?
(A) 28.8 %
(B) 38.8 %
(C) 68.8 %
(D) 88.8 %
(E) 98.8 %