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Question: Answered & Verified by Expert
A block of mass $m$ is moving on a rough horizontal surface. The coefficient of kinetic friction between block and surface is $\mu_{k}$, The net force exerted by the surface on the block is $\quad(\mathrm{g}=$ acceleration due to gravity $)$
PhysicsLaws of MotionMHT CETMHT CET 2020 (15 Oct Shift 2)
Options:
  • A $\operatorname{mg}\left(1+\mu_{\mathrm{k}}\right)^{1 / 2}$
  • B $\left[\mathrm{mg}\left(1+\mu_{\mathrm{k}}\right)\right]^{1 / 2}$
  • C $\mathrm{mg}\left(1+\mu_{\mathrm{k}}^{2}\right)$
  • D $\mathrm{mg}\left(1+\mu_{\mathrm{k}}^{2}\right)^{1 / 2}$
Solution:
2473 Upvotes Verified Answer
The correct answer is: $\mathrm{mg}\left(1+\mu_{\mathrm{k}}^{2}\right)^{1 / 2}$
Given that:
If body of mass \(m\) moving with rough horizontal surface Kinetic fiction = u
\(\begin{aligned} F_{\text {net }} &=\sqrt{f_{1}^{2}+f_{3}{ }^{2}} \\ &=\sqrt{\left(m g^{2}\right)^{2}+(l m g)^{2}} \end{aligned}\)
\(F=m g \sqrt{1+\mu^{2}}=\) option \(A\) is correct

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