In the case of fluid, Bernoulli's theorem expresses the application of principle conservation of

Options

A. Linear momentum
B. energy
C. mass
D. angular momentum

Answer

To solve the question regarding Bernoulli's theorem and its relation to the principle of conservation, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Bernoulli's Theorem**:
Bernoulli's theorem states that for an incompressible, non-viscous fluid flowing in a streamline, the total mechanical energy along a streamline is constant. This can be expressed mathematically as:
\[ P + \rho gh + \frac{1}{2} \rho v^2 = \text{constant} \]
where:
- \( P \) = pressure energy per unit volume
- \( \rho gh \) = potential energy per unit volume (due to height)
- \( \frac{1}{2} \rho v^2 \) = kinetic energy per unit volume

2. **Identifying the Components**:
- The term \( P \) represents the pressure energy.
- The term \( \rho gh \) represents the potential energy associated with the height of the fluid.
- The term \( \frac{1}{2} \rho v^2 \) represents the kinetic energy of the fluid.

3. **Relating to Conservation Principles**:
The equation can be viewed as a statement of the conservation of energy principle, where the sum of pressure energy, potential energy, and kinetic energy remains constant for a flowing fluid.

4. **Conclusion**:
Thus, Bernoulli's theorem expresses the application of the principle of conservation of energy in the context of fluid dynamics.

### Final Answer:
Bernoulli's theorem expresses the application of the principle of conservation of **energy**.