_______also causes gradual wear and tear of machine parts

Options

A. Friction
B. Gravitational force
C. Static friction
D. Muscular force

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a factor that causes gradual wear and tear of machine parts. This implies we are looking for a physical phenomenon that affects the durability and lifespan of machines.

2. **Identifying the Relevant Concept**: In physics, friction is the force that opposes the relative motion of two surfaces in contact. It is a common phenomenon that occurs in various mechanical systems.

3. **Analyzing the Effects of Friction**: When two surfaces rub against each other, friction generates heat and causes material to be removed from the surfaces. Over time, this leads to wear and tear, which can affect the performance and efficiency of machines.

4. **Conclusion**: Based on the analysis, we conclude that friction is the agent responsible for the gradual wear and tear of machine parts. Therefore, the answer to the question is "friction."

**Final Answer**: Friction also causes gradual wear and tear of machine parts.

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