AMU Medical AMU Solved Paper-2013

  • question_answer
    A 40 kg slab rests on a frictionless floor. A 10 kg block rests on top of the slab (as shown in the figure). The coefficient of static friction \[{{\mu }_{s}}\]between the block and the slab is 0.60, whereas their kinetic friction coefficient \[{{\mu }_{k}}\] is 0.40. The 10 kg block is pulled by a horizontal force (100.0 N) i. The resulting accelerations of the block and slab will be

    A)  \[(2.0\,m/{{s}^{2}})\,i,0\]

    B)  \[(2.0\,m/{{s}^{2}})\,i,-(2.0\,m/{{s}^{2}})\,i\]

    C)  \[(6.0\,m/{{s}^{2}})\,i,-(1.0\,m/{{s}^{2}})\,i\]

    D)  \[(4.0\,m/{{s}^{2}})\,i,0\] (Take \[g=10\,m/{{s}^{2}}\])

    Correct Answer: C

    Solution :

                    \[f=0.6\times 10\times 9.8\,N=58.8\,N\] Since the applied force is greater than f therefore the block will be in motion so, we should consider \[{{f}_{k}}\]. \[{{f}_{k}}=0.4\times 10\times 9.8\,N\]or    \[{{f}_{k}}=4\times 9.8\,N\] This would cause acceleration of 40 kg block acceleration \[=\frac{4\times 9.8}{40}=(0.98)\,i\,m{{s}^{-2}}=(1)\,i\,m{{s}^{-2}}\] Acceleration of 10 kg block\[\frac{58.8}{10}=(5.88)\,i=(6)\,i\,m/{{s}^{2}}\]


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