Topic: Thermodynamics
Only rocket engines can be propelled to space because
- A. They can generate very high thrust
- B. They have high propulsion efficiency
- C. These engines can work on several fuels
- D. They are not air-breathing engines
Answer: D. They are not air-breathing engines
Explanation: On earth, air tends to inhibit the exhaust gases from the engine (rocket), it reduce the thrust. However in space there is no atmosphere, the exhaust gases can exit much easier and faster, thus increasing the thrust. Thrust depends upon the speed of the exhaust gases and the mass of gas being expelled each second. Therefore the rocket engine actually works better in space than here on earth.