MCQ 11 Mark
Friction due to fluids is called.
- AForce
- BPressure
- CFriction
- ✓Drag
Answer
View full question & answer→Correct option: D.
Drag
50 questions · timed · auto-graded
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Type of road surfaces
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$P$
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$Q$
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$R$
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$S$
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Stopping distance(m)
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$18$
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$15$
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$19$
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$27$
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The road $Q$ provides the maximum friction, I since the stopping distance for surface $Q$ is the lowest.
Lubricants are thick liquids that make rough surfaces smooth and slippery. The application of lubricants reduces the friction between two surfaces moving relative to each other. Since the use of lubricants between two surfaces reduces the value of $X, X$ must be the force of friction.
A person will not be able to climb a mountain if frictional force i.e., a contact force is absent.
Irregularities on surfaces offer resistance to the motion of an object over it. This resistance is called friction. The more the irregularities on the surface, the more is the friction. Hence, more force is required to move an object placed on an irregular surface. Since irregularities present on a grass field are more than those present on a marble floor, more force is required to move a box placed in the grass field. Boxes $I$ and $II$ are placed in a grass field. Therefore, boxes $I$ and $II$ require more forces to be moved than those required by boxes $III$ and $IV$. The opposing force of friction does not remain the same for heavier and lighter objects. Frictional force is greater for heavier objects and smaller for lighter objects. Since box $II$ is heavier than box $I$, box $II$ requires the maximum force to be moved.
We know that friction force acts in an opposite direction to the direction in which an object moves. The maximum frictional force present between two objects is static friction. And sliding friction is smaller than static friction. And rolling friction is much less than sliding friction. The static friction is always greater than sliding friction.
The block stops after traveling some distance, i.e., its speed decreases. This implies that a force is applied in the direction opposite to its motion. The block is moving from left to right. Therefore, the frictional force acting on the block is toward the left.