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प्रश्न
Answer in short.
State the laws of static friction.
उत्तर
- First law: The limiting force of static friction (FL) is directly proportional to the normal reaction (N) between the two surfaces in contact.
FL ∝ N
∴ FL = μS N
where, μS = constant called the coefficient of static friction. - Second law: The limiting force of friction is independent of the apparent area between the surfaces in contact, so long as the normal reaction remains the same.
- Third law: The limiting force of friction depends upon materials in contact and the nature of their surfaces.
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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.
Explain how lubricants help in reducing 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?
