Which of the following operates strictly on the principle of conservation of linear momentum?
A. Rocket
B. Hovercraft
C. Aeroplane
D. Helicopter
Answer: Option A
Solution (By JKExamLibrary)
A rocket works on the principle of conservation of linear momentum. As the exhaust gases are expelled downward at high velocity, they carry downward momentum. To conserve the total momentum of the system (which is initially zero), the rocket must acquire an equal and opposite (upward) momentum, propelling it forward.
Explanation:
Fuse wire must melt easily (low melting point) to break circuit on overload, and have high resistance to produce sufficient heat (I²R). Materials: tin-lead alloy. Copper not used as fuse.
Explanation:
1 kWh = 1000 W × 3600 s = 3,600,000 J = 3.6 × 10⁶ J. This is a standard conversion. Power (watt) × time (hour) gives energy. 1 watt = 1 J/s. Remember this for electricity bills.
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