If maching is lubricated with oil

Options

A. the machanical adventage of the maching of the maching increses
B. the machanical efficiency of the maching of the maching increses
C. both its machanical advantage and afficiency increses
D. in efficiency increases but its machanical advantage decreases

Explanation

To solve the question regarding the effects of lubricating a machine with oil, we will analyze how lubrication impacts mechanical advantage and mechanical efficiency.

### Step-by-Step Solution:

1. **Understanding Mechanical Advantage (MA)**:
- Mechanical Advantage is defined as the ratio of output force (F2) to input force (F1).
- Formula: \( MA = \frac{F2}{F1} \)

2. **Understanding Mechanical Efficiency (η)**:
- Mechanical Efficiency is defined as the ratio of output work (W_out) to input energy (W_in).
- Formula: \( η = \frac{W_{out}}{W_{in}} \)

3. **Effect of Lubrication on Friction**:
- When a machine operates, friction is present between its moving parts, which resists motion and reduces output work.
- Lubricating the machine with oil reduces friction, allowing parts to move more freely.

4. **Impact on Output Work**:
- With reduced friction, the output work (W_out) increases because the machine can perform more useful work with the same input energy (W_in).
- Thus, \( W_{out} \) increases when lubrication is applied.

5. **Calculating Mechanical Efficiency Post-Lubrication**:
- Since the output work increases while the input energy remains constant, the mechanical efficiency (η) of the machine increases.
- Therefore, \( η_{new} > η_{old} \).

6. **Impact on Mechanical Advantage**:
- The mechanical advantage is influenced by the forces involved. However, lubrication primarily affects the efficiency rather than the ratio of forces.
- Without specific information about the output and input forces, we cannot definitively state that mechanical advantage increases or decreases. Thus, we cannot conclude that MA changes significantly.

7. **Conclusion**:
- After lubrication, we can confidently say that the mechanical efficiency of the machine increases due to reduced friction. However, we cannot make a definitive statement about mechanical advantage without additional information on forces.

### Final Answer:
The correct option is that the **Mechanical efficiency of the machine increases**.