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⚛️ Physics  ·  Mechanical Properties of Fluids  ·  NEET & JEE

An ice cube floats in a glass of water. When it melts completely, the water level:

Answer: Stays the same.

  • A Stays the same
  • B Rises
  • C Falls
  • D Depends on ice density

Correct answer: A. Stays the same

Explanation: Floating ice displaces water equal to its weight. When ice melts, it produces exactly that same weight of water. The water level remains unchanged.

Continuity Equation: Narrow Pipe → Faster FlowA₁, v₁ (wide, slow)A₂, v₂ (narrow, fast)A₁v₁ = A₂v₂ (continuity)Smaller area → higher speed → (by Bernoulli) LOWER pressure

Since the same volume of fluid must pass every cross-section per second (continuity), the fluid speeds up where the pipe narrows; Bernoulli's equation then says this faster-moving fluid has lower pressure - the principle behind a venturi meter and an aircraft wing's lift.

Concept context

Pressure, buoyancy, Bernoulli equation, viscosity, and surface tension.

Read the full Mechanical Properties of Fluids notes →