9th Class Science Force and laws of motion Question Bank Force and Laws of Motion

  • question_answer
    A body of mass 60 kg is dragged with just enough force to start moving on a rough surface with coefficients of static and kinetic frictions 0.5 and 0.4 respectively. On applying the same force, what is the acceleration?

    A)  \[0.\text{98 m}/{{\text{s}}^{\text{2}}}\]  

    B)  \[\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}}\]

    C)  \[0.\text{54 m}/{{\text{s}}^{\text{2}}}\]

    D)  \[\text{5}.\text{292 m}/{{\text{s}}^{\text{2}}}\]

    Correct Answer: A

    Solution :

     force being applied even after the body has started moving             \[={{\mu }_{s}}mg\] Force of kinetic friction in picture = ma So        \[a=({{\mu }_{s}}-{{\mu }_{k}})g\]                \[=0.1\times 9.8=0.98\]


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