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4.2 friction — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics4.2 friction1 Mark
MCQ
A block of mass $M$ rests on a rough horizontal table. A steadily increasing horizontal force is applied such that the block starts to slide on the table without toppling. The force is continued even after sliding has started. Assume the coefficients of static and kinetic friction between the table and the block to be equal. The correct representation of the variation of the frictional force $f$, exerted by the table on the block with time $t$ is given by
  • ✓

  • B

  • C

  • D

✓

Answer

Correct option: A.

a
(a)

Force of friction is self adjusting. When applied force is increased friction, first increases till it reaches a maximum value called limiting friction.

If applied force is further increased, then friction does not increases further and body begins to move.

Force of friction then remains constant and its value is given by

$f=\mu N$

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