Which one of the following is not used to reduce friction

  • A

    Oil

  • B

    Ball bearings

  • C

    Sand

  • D

    Graphite

Similar Questions

A conveyor belt is moving at a constant speed of $2\, ms^{-1}$. A box is gently dropped on it. The coefficient of friction between them is $\mu  = 0.5$. The distance that the box will move relative to belt before coming to rest on it, (taking $g = 10\, ms^{-2}$) is  ........  $m$.

A force acts on a block as shown in figure. Find time when block loses contact with surface.

$Assertion$ : Angle of repose is equal to the angle of limiting friction.
$Reason$ : When the body is just at the point of motion, the force of friction in this stage is called limiting friction.

  • [AIIMS 2008]

The limiting friction between two bodies in contact is independent of

A uniform rope lies on a horizontal table so that a part of it hangs over the edge. The rope begins to slide down when the length of the hanging part is $25\%$ of the entire length. The coefficient of friction between the rope and the table is