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प्रश्न
Answer in short.
Explain how lubricants help in reducing friction.
उत्तर
- The friction between lubricant to surface is much less than the friction between the two same surfaces. Hence using lubricants reduces the friction between the two surfaces.
- When the lubricant is applied to machine parts, it fills the depression present on the surface in contact. Thus, less friction occurs between machine parts.
- The application of lubricants also reduces wear and tear of machine parts which in turn reduces friction.
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संबंधित प्रश्न
Answer in one sentence.
Define friction.
Answer in one sentence.
Why force of static friction is known as ‘self-adjusting force’?
Answer in one sentence.
Name two factors on which the coefficient of friction depends.
State any four methods to reduce friction.
Answer in short.
What is rolling friction? How does it arise?
Answer in short.
State the laws of static friction.
Answer in short.
State the laws of kinetic friction.
Answer in short.
State advantages of friction.
State disadvantages of friction.
Long answer type question.
Define coefficient of static friction and coefficient of kinetic friction. Give the necessary formula for each.
Calculate the coefficient of static friction for an object of mass 50 kg placed on horizontal table pulled by attaching a spring balance. The force is increased gradually it is observed that the object just moves when spring balance shows 50 N.
Answer the following.
A block of mass 37 kg rests on a rough horizontal plane having coefficient of static friction 0.3. Find out the least force required to just move the block horizontally.
A body of mass 37 kg rests on a rough horizontal surface. The minimum horizontal force required to just start the motion is 68.5 N. In order to keep the body moving with constant velocity, a force of 43 N is needed. What is the value of coefficient of static friction?
