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Statement-1: Submarine crews are warned not to let the vessel come to rest on the ocean floor. Statement-2: The net force that a liquid exerts on a fully submerged body can act in the downward direction.
- Statement-1 is true, statement-2 is true and statement-2 is the correct explanation of statement-1.
- Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation of statement-1.
- Statement-1 is true, statement-2 is false.
- Statement-1 is false, statement-2 is true.
Correct answer: Statement-1 is true, statement-2 is true and statement-2 is the correct explanation of statement-1.
Solution
Buoyancy exists because liquid pressure on the lower surface (upward) exceeds that on the upper surface (downward). If a submarine rests flat on the floor, water can be sealed out from underneath, so there is no upward pressure on the base. Then only the downward pressure on the top acts, plus suction, producing a large net downward force that can pin the vessel to the bottom. So Statement-1 is true, Statement-2 is true, and Statement-2 correctly explains Statement-1.
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