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Zorluk: KolayFriction and Resistance

A maintenance team needs to move a heavy steel generator across a flat concrete floor. Arrange the following methods in order from the HIGHEST amount of frictional resistance to the LOWEST amount of frictional resistance.

  1. 1Dragging the generator directly across the dry concrete floor.
  2. 2Sliding the generator across the floor after applying a thick layer of industrial lubricant.
  3. 3Placing the generator on cylindrical steel rollers before moving it.

Cevap

The correct order from highest to lowest resistance is: dragging directly on dry concrete, sliding with industrial lubricant, and placing on steel rollers.
Dry sliding friction creates the most resistance due to direct, rough surface-to-surface contact. Lubricating the surface reduces this resistance by creating a fluid film between the objects, lowering the friction coefficient. However, rolling friction (using rollers) is the most efficient method and creates the absolute least resistance, as it prevents the surfaces from scraping against each other entirely.

Adım Adım Çözüm

1
Identify the primary type of friction acting in each of the three moving methods.
Dragging directly involves dry sliding friction; using lubricant involves fluid or mixed friction; using steel rollers involves rolling friction.
Recognizing the physical mechanism at the contact surface is the first step in comparing resistance levels.
2
Compare the relative magnitudes of these different types of friction.
Dry sliding friction provides the greatest resistance due to interlocking surface irregularities. Lubrication reduces this contact, lowering resistance. Rolling friction provides the least resistance as sliding is eliminated.
Fundamental mechanical principles state that, for a given load, dry kinetic friction is generally greater than fluid friction, which in turn is greater than rolling friction.
3
Order the methods from highest frictional resistance to lowest.
Highest is dry dragging, middle is lubricated sliding, lowest is steel rollers.
This matches the sequence requirements specified in the question stem.

Anahtar Kavram

Types and relative magnitudes of mechanical friction
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