CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2008

  • question_answer
    A body of mass 4 kg is accelerated upon b constant force, travels a distance of 5 m in the first second and a distance of 2 m in the third second. The force acting on the body is

    A)  2 N                                       

    B)  4 N

    C)  6 N                                       

    D)  8 N

    Correct Answer: C

    Solution :

    Distance travelled by the body in \[{{n}^{th}}\] second is given by                 \[{{S}_{n}}=u+\frac{a}{2}\,(2n-1)\]                 \[5=u+\frac{a}{2}\,(2\times 1-1)\]                 \[5=u+\frac{a}{2}\]                                         ... (i)                 \[2=u+\frac{a}{2}(2\times 3-1)\]                 \[2=u+\frac{5}{2}a\]                                       ... (ii) Solving Eqs. (i) and (ii), we get                 \[a=-\frac{6}{4}m/{{s}^{2}}\]ie, body is decelerating                 mass = 4 kg and        \[F=m\times a=4\times \frac{6}{4}=6\,N\]


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