Chhattisgarh PMT Chhattisgarh PMT Solved Paper-2007

  • question_answer
      Car A starts initially with the acceleration \[{{a}_{1}},\] after 2 s the car B starts with acceleration \[{{a}_{2}}.\]If in \[{{\text{5}}^{\text{th}}}\text{s}\] both car travels same distance, then the ratio of a \[{{a}_{1}}\] and \[{{a}_{2}}\] will be

    A)  5 : 9                                      

    B)  5 : 7

    C)  9 : 5                                      

    D)  9 : 7

    Correct Answer: A

    Solution :

    Distance travelled in 5th  second \[{{S}_{n}}=u+\frac{a}{2}(2n-1)\] \[\therefore \] Distance travelled by car A in 5th second                 \[{{S}_{A}}=0+\frac{{{a}_{1}}}{2}(2\times 5-1)=\frac{9{{a}_{1}}}{2}\] Distance travelled by car B in 5th second                 \[{{S}_{B}}=0+\frac{{{a}_{2}}}{2}(2\times 3-1)=\frac{5{{a}_{1}}}{2}\] Given,   \[{{S}_{A}}={{S}_{B}}\] \[\therefore \]                  \[\frac{9{{a}_{1}}}{2}=\frac{5{{a}_{2}}}{2}\] \[\therefore \]                  \[\frac{{{a}_{1}}}{{{a}_{2}}}=\frac{5}{9}\]


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