Which is correct option in following?

Question

Accepted Answer

Explanation:

1. **Why Option 4 is Correct: Static fraction > Sliding fraction > Rolling fraction**

- **Static Friction**: Static friction is the force that must be overcome to start moving an object at rest. It is generally the highest among the three types of friction because it involves breaking the initial bonds or overcoming the initial resistance between the surfaces in contact. This is why it is greater than both sliding and rolling friction.
   
   - **Sliding Friction**: Once an object is in motion, it experiences sliding friction, which is typically less than static friction. This is because the initial resistance has already been overcome, and the object is now moving, which requires less force to maintain motion compared to starting it.
   
   - **Rolling Friction**: Rolling friction occurs when an object rolls over a surface. It is usually the smallest of the three types of friction because the contact area between the surfaces is minimized, and rolling involves less resistance compared to sliding. This is why rolling friction is less than both static and sliding friction.

2. **Why the Other Options are Incorrect**:

- **Option 1: Sliding fraction > Rolling fraction > Static fraction**: This option incorrectly suggests that sliding friction is greater than static friction, which contradicts the fundamental understanding that static friction is typically higher because it involves overcoming the initial resistance to motion.

- **Option 2: Rolling fraction > Sliding fraction > Static fraction**: This option incorrectly places rolling friction as the highest, which is not accurate. Rolling friction is generally the lowest due to the reduced contact area and resistance, as explained earlier.

- **Option 3: Rolling fraction > Static fraction > Sliding fraction**: This option incorrectly suggests that rolling friction is greater than static friction, which is not true. Static friction is the highest because it involves initiating motion, while rolling friction is the lowest due to the nature of rolling contact.

By understanding the nature of these different types of friction, it becomes clear why Option 4 is the correct choice, as it accurately reflects the typical hierarchy of frictional forces: static friction being the greatest, followed by sliding friction, and then rolling friction being the least.