MCQ
A block is lying on an inclined plane which makes $60^{\circ}$ with the horizontal. If coefficient of friction between block and plane is $0.25$ and $g=10 \mathrm{~m} / \mathrm{s}^2$, then acceleration of the block when it moves along the plane will be
  • A
    $2.50 \mathrm{~m} / \mathrm{s}^2$
  • B
    $5.00 \mathrm{~m} / \mathrm{s}^2$
  • $7.4 \mathrm{~m} / \mathrm{s}^2$
  • D
    $8.66 \mathrm{~m} / \mathrm{s}^2$

Answer

Correct option: C.
$7.4 \mathrm{~m} / \mathrm{s}^2$
$ a=g(\sin \theta-\mu \cos \theta)=10\left(\sin 60^{\circ}-0.25 \cos 60^{\circ})\right.$
$ a=7.4 m / s ^2$

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