A body of weight $64 \mathrm{~N}$ is pushed with just enough force to start it moving across a horizontal…

A body of weight $64 \mathrm{~N}$ is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body is (Acceleration due to gravity $=g$ )
  1. $\frac{g}{6.4}$
  2. $0.64 g$
  3. $\frac{g}{32}$
  4. $0.2 \mathrm{~g}$

Solution

$w=64 \mathrm{~N}, \mu_i=0.6, \mu_k=0.4$ Acceleration of the body $\begin{aligned} & =\left(\mu_{,}-\mu_k\right) g \\ & =(0.6-0.4) \times g \\ & =0.2 \mathrm{~g} \mathrm{~m} / \mathrm{s}^2\end{aligned}$

Asked in: AP EAMCET 2001

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