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Conservation of Energy in Fluid Flow

Elijah Ramirez

Elijah Ramirez

8 min read

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Study Guide Overview

This study guide covers fluid dynamics with a focus on Bernoulli's equation and its applications. It explains the equation's components (pressure, velocity, height), assumptions (incompressible fluid, streamline flow, negligible viscosity), and provides problem-solving strategies. The guide also connects Bernoulli's equation to the continuity equation and the concept of energy conservation, and offers practice questions and exam tips.

Fluid Dynamics: Energy Conservation and Bernoulli's Principle 🌊

Hey there, future AP Physics 2 master! Let's dive into the world of fluid dynamics, focusing on how energy is conserved when fluids are in motion. This is a crucial topic, so let's make sure you've got it down pat!

Bernoulli's Equation: The Heart of Fluid Flow

What is it?

Bernoulli's equation is essentially a statement of energy conservation for fluids. It relates pressure, velocity, and height at different points in a flowing fluid. Think of it as the fluid version of KE + PE = constant.

Key Concept

It's a powerful tool, but it comes with some assumptions:

  • Incompressible Fluid: The fluid's density remains constant.
  • Streamline Flow: The flow is smooth, without turbulence.
  • Negligible Viscosity: Internal friction within the fluid is minimal.

Don't sweat these assumptions too much; the AP exam usually provides scenarios where these conditions are met.

The Equation

Here's the star of the show:

P1+12ρv12+ρgh1=P2+12ρv22+ρgh2P_1 + \frac{1}{2} \rho v_1^2 + \rho g h_1 = P_2 + \frac{1}{2} \rho v_2^2 + \rho g h_2

Where:

  • PP is pressure (in Pascals, Pa)
  • ρ\rho is fluid density (in kg/m³)
  • vv is fluid velocity (in m/s)
  • gg is the acceleration due to gravity (9.8 m/s²)
  • hh is the height above a reference point (in meters)
Memory Aid

Remember this as "Pressure + Kinetic Energy + Potential Energy = Constant"

Bernoulli's Equation

Key Concepts

  • Pressure: Force per unit area. Higher pressure can push the fluid faster.
  • Kinetic Energy: Energy of motion, related to fluid velocity. Faster fluid = more KE.
  • Potential Energy: Energy of position, related to height. Higher fluid = more PE.
Quick Fact

Bernoulli's principle is a direct consequence of the conservation of energy. It states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

Applying Bernoulli's Equation: Problem-Solving Strategies

Step-by-Step

  1. **Identify ...

Question 1 of 11

🚀 When a fluid flows through a pipe and its velocity increases, what happens to the pressure, assuming height remains constant?

The pressure increases

The pressure decreases

The pressure remains the same

The pressure fluctuates randomly