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A particle of mass \mathrm{m} is moving in a circular path of constant radius \mathrm{ r} such that its centripetal acceleration \mathrm{ (a)} is varying with time \mathrm{ t \: \: as \: \: a=k^{2} r t^{2},} where \mathrm{ k} is a constant. The power delivered to the particle by the force acting on it is given as
 

Option: 1

zero


Option: 2

\mathrm{m k^{2} r^{2} t^{2}}


Option: 3

\mathrm{m k^{2} r^{2} t}


Option: 4

\mathrm{m k^{2} rt}


Answers (1)

best_answer

\mathrm{a=k^{2} r t^{2}}\\

\because \text{since centripetal acceleration}

\mathrm{a_{c}=\frac{v^{2}}{r} =k^{2} r t^{2}} \\

\mathrm{v^{2} =k^{2} r^{2} t^{2}} \\

\mathrm{v =k r t}

Here speed is variable, therefore particle is performing non-uniform circular motion

\mathrm{\text { Power }(P) =F_{\text {tangential }} \times \text { speed } }\\

\mathrm{=m a_{t} \times v} \\

\mathrm{a_{t}=\frac{d v}{d t} =\frac{d}{d t}(k r t)=k r} \\

\mathrm{p =m k r \times k r t} \\

\mathrm{p =m k^{2} r^{2} t}

Hence the correct option is 3

Posted by

Devendra Khairwa

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