Question

Given below are examples of friction shown in List-I with their respective types of friction in List-II.
List-I: (a) Pushing a chair, (b) Sea waves, (c) Moving heavy stationary objects, (d) Skating
List-II: (i) Sliding, (ii) Rolling, (iii) Fluid, (iv) Static

• A. (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
• B. (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
• C. (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
• D. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)

Hint:

Static friction is always the strongest type of friction, while rolling friction is the weakest. This is why it's harder to start moving a heavy box than to keep it sliding.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Friction is the resistance offered by surfaces in contact. Its type depends on whether the object is stationary, sliding, rolling, or moving through a medium like water or air.
Step 2: Detailed Explanation:

1. Pushing a chair (a): The legs of the chair rub against the floor, which is Sliding friction (i).
2. Sea waves (b): This involves movement through water (a liquid), which is Fluid friction (iii).
3. Moving heavy stationary objects (c): The resistance encountered before the object starts moving is Static friction (iv).
4. Skating (d): While ice skating involves a thin film of water, in the context of general "skating" (like roller skates), it is characterized by Rolling friction (ii).
Step 3: Final Answer:
The matching pairs are (a)-(i), (b)-(iii), (c)-(iv), and (d)-(ii).

Answer 2

This is a matching-type question with four candidate mappings between friction scenarios and friction types. Instead of matching each item individually, let's test each full option as a set of four claims and see which one is internally consistent with the physics of each scenario.

1. Option 1: (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv). This pairs moving heavy stationary objects with rolling friction and skating with static friction. Overcoming a heavy stationary object's resistance to start moving is a static-friction situation, not rolling, and skating involves continuous rolling motion, not a static condition. Two of the four pairings are swapped incorrectly, so this option is wrong.
2. Option 2: (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii). This calls pushing a chair static friction, but once the chair is actually sliding across the floor, the friction resisting that motion is sliding friction, not static. It also labels sea waves as rolling friction and moving a heavy object as sliding friction, both mismatched with what those scenarios actually involve. This option is wrong.
3. Option 3: (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii). Pushing a chair across the floor is sliding friction, since the chair legs slide against the surface. Sea waves moving through water and air is fluid friction. Getting a heavy stationary object to start moving means overcoming static friction, the resistance before motion begins. Skating involves the wheels or blade rolling along the surface, which is rolling friction. All four pairings match their physical description correctly.
4. Option 4: (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii). This calls pushing a chair rolling friction, but a chair does not roll, it slides. It also swaps sea waves to sliding friction and skating to fluid friction, neither of which fits. This option is wrong.

Only the third option keeps every pairing consistent with the actual physical mechanism at play in each scenario.

Therefore, the correct answer is (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii).