A block of mass 5 kg is placed on a rough horizontal surface having coefficient of friction 0.5 . If a horizontal force of 60 N is acting on it, then the acceleration of the block is (Acceleration due to gravity, $g=10 \mathrm{~ms}^{-2}$ ).

• Correct answer
  A

  $7 \mathrm{~ms}^{-2}$
• B

  $5 \mathrm{~ms}^{-2}$
• C

  $10 \mathrm{~ms}^{-2}$
• D

  $15 \mathrm{~ms}^{-2}$

Solution

Acceleration of the block is $\begin{aligned} & \mathrm{a}=\frac{60-25}{5}=\frac{35}{5} \\ & =7 \mathrm{~m} / \mathrm{s}^2 \\ & \mathrm{f}=5 \times 10 \times 0.5 \\ & =25 \mathrm{~N}\end{aligned}$

Hence, the correct answer is option: 'A'.