Which of the following are correct for rolling friction

Options

A. The extent of deformation of the surfaces in content
B. It is lesser than kinetic and limiting friction
C. It is inversely proportional to the radius of the rolling body.
D. All the above

Answer

To solve the question regarding rolling friction, we need to analyze each statement provided in the options and determine their correctness based on the principles of physics.

### Step-by-Step Solution:

1. **Understanding Rolling Friction:**
- Rolling friction occurs when an object rolls over a surface. It is the resistance that opposes the motion of the rolling object.

2. **Analyzing the Statements:**
- **Statement 1:** "The extent of deformation of the surface in contact."
- This statement is correct because rolling friction involves some deformation of both the rolling object and the surface it rolls on. However, this deformation is typically less than that experienced in sliding friction.

- **Statement 2:** "It is lesser than kinetic and limiting friction."
- This statement is also correct. Rolling friction is generally much less than both kinetic friction (which occurs when two surfaces slide against each other) and limiting friction (the maximum frictional force before sliding occurs). This is one reason why wheels are used to facilitate motion.

- **Statement 3:** "It is inversely proportional to the radius of the rolling body."
- This statement is correct as well. The rolling friction force decreases as the radius of the rolling body increases. A larger radius means that the contact area is effectively reduced, leading to less deformation and, hence, less friction.

3. **Conclusion:**
- Since all three statements are correct, the answer to the question is **Option 4: All of the above.**

### Final Answer:
All of the above statements regarding rolling friction are correct.

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