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Laws Of Motion

Question
CBSEENPH11020470

A block rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg) is (take g = 10 m/s2 )
  • 2.0

  • 4.0

  • 1.6 

  • 2.4

Solution

A.

2.0

Let the mass of block be m.
Frictional force in rest position
F = mg sin 30

10 space equals space straight m space straight x space 10 space straight x space 1 half
space straight m space equals space fraction numerator 2 space straight x space 10 over denominator 10 end fraction space equals space 2 space kg