RAJASTHAN PMT Rajasthan - PMT Solved Paper-2003

  • question_answer
    Two springs A and B having force constants k each are arranged (i) in parallel and (ii) in series. A mass M is attached to two arrangements separately. If time period in case (i) is\[{{T}_{1}}\]1 and in case (ii) is \[{{T}_{1}}\] then ratio\[\frac{{{T}_{1}}}{{{T}_{2}}}\] is                                                              

    A)    \[1\]                                    

    B)  \[2\]

    C)  \[0.5\]                 

    D)         \[0.25\]

    Correct Answer: C

    Solution :

    In case (i), springs are connected in parallel, so, effective force constant is \[{{k}_{1}}=k+k=2k\] In case (ii), springs are connected in series so, effective force constant \[{{k}_{2}}\] is given by \[\frac{1}{{{k}_{2}}}=\frac{1}{k}+\frac{1}{k}=\frac{2}{k}\]           \[\Rightarrow \]     \[{{k}_{2}}=\frac{k}{2}\] In case (i), time period                 \[T{{ & }_{1}}=2\pi \sqrt{\frac{M}{{{k}_{1}}}}=2\pi \sqrt{\frac{M}{2k}}\] and in case (ii)/ time period                         \[T{{ & }_{2}}=2\pi \sqrt{\frac{M}{{{k}_{2}}}}=2\pi \sqrt{\frac{M}{k/2}}\]                                         \[2\pi \sqrt{\frac{2M}{k}}\] \[\therefore \]           \[\frac{{{T}_{1}}}{{{T}_{2}}}=\sqrt{\frac{1}{4}}\]                                          \[=\frac{1}{2}=0.5\]


You need to login to perform this action.
You will be redirected in 3 sec spinner