Variable Mass (conceptual)
In rocket propulsion, thrust arises primarily due to:
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About This Question
- Subject
- physics
- Chapter
- laws of motion
- Topic
- variable mass (conceptual)
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
Momentum carried away by exhaust gases
- Law of Conservation of Momentum: In a closed system with no external forces, total momentum remains constant.
- Rocket Mechanism: A rocket expels gases downward at extremely high velocities (vex). This 'Action' carries away backward momentum.
- Thrust Calculation: By Newton's Third Law, the exhaust gases exert an equal and opposite force (Thrust) on the rocket fuel chamber: F=vex(dtdm).
- Correction: Rocket propulsion does NOT require air; it works best in a vacuum. It is purely an internal action-reaction process.
This easy difficulty physics question is from the chapter laws of motion, covering the topic of variable mass (conceptual). It appeared in the 2025 exam.
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