Which one of the following statements is incorrect? 

  • [NEET 2018]
  • A

    Rolling friction is smaller than sliding friction.

  • B

    Limiting value of static friction is directly proportional to normal reaction.

  • C

    Coefficient of sliding friction has dimensions of length.

  • D

    Frictional force opposes the relative motion.

Similar Questions

A block of mass $m$ is on an inclined plane of angle $\theta$. The coefficient of friction between the block and the plane is $\mu$ and $\tan \theta>\mu$. The block is held stationary by applying a force $\mathrm{P}$ parallel to the plane. The direction of force pointing up the plane is taken to be positive. As $\mathrm{P}$ is varied from $\mathrm{P}_1=$ $m g(\sin \theta-\mu \cos \theta)$ to $P_2=m g(\sin \theta+\mu \cos \theta)$, the frictional force $f$ versus $P$ graph will look like

  • [IIT 2010]

The limiting friction between two bodies in contact is independent of

A mass of $4\; kg$ rests on a horizontal plane. The plane is gradually inclined until at an angle $\theta= 15^o$ with the horizontal, the mass just begins to slide. What is the coefficient of static friction between the block and the surface ?

$A$ block $P$ of mass m is placed on a frictionless horizontal surface. Another block Q of same mass is kept on $P$ and connected to the wall with the help of a spring of spring constant k as shown in the figure. ${\mu _s}$ is the coefficient of friction between$  P$ and $ Q$. The blocks move together performing SHM of amplitude $A$. The maximum value of the friction force between $P$ and $Q$ is

  • [IIT 2004]

The limiting friction between two bodies in contact is independent of