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Kinetic Friction - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Kinetic Friction is considered one of the most asked concept.

  • 6 Questions around this concept.

Solve by difficulty

A rocket is fired  vertically from the earth with an acceleration of 2g, where g is the gravitational acceleration.  On an inclined plane inside the rocket, making an angle θ with the horizontal, a point object of mass m is kept.  The minimum coefficient of friction µmin between the mass and the inclined surface such that the mass does not move is :

The upper half of an inclined plane with inclination  \phi is perfectly smooth while the lower half is rough .A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is given by

Concepts Covered - 1

Kinetic Friction
  1. Kinetic friction occurs when there is relative motion between two bodies that are in contact.

  2. When two bodies slip over each other, the force of friction is called kinetic friction.

  3. It is a constant friction force, i.e, it does not depend upon the speed of relative motion.

  4. The magnitude of the kinetic friction is proportional to the normal force acting between the two bodies.

  5. It is denoted by:- 

$\begin{aligned} & f_K \alpha N \\ & f_K=\mu_K N \\ & f_K=\text { kinetic friction } \\ & \mu_K=\text { coefficient of kinetic friction is constant } \\ & N=\text { reaction } \\ & \text { Coefficient of friction }\left(\mu_k\right)\end{aligned}$

  • It is unitless and dimensionless.
  • It depends on the nature and material of the two bodies in contact.
  • It doesn't depend on the speed of the sliding bodies.

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Kinetic Friction

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