MCQ
A particle of mass $M$ is moving in a circle of fixed radius $R$ in such a way that its centripetal acceleration at time $t$ is given by $n^2Rt^2$ where $n$ is a constant. The power delivered to the particle by the force acting on it, is
  • A
    $\frac{1}{2}\,M\,{n^2}\,{R^2}{t^2}$
  • $M\,{n^2}{R^2}{t^2}$
  • C
    $M\,n\,{R^2}{t^2}$
  • D
    $M\,n\,{R^2}t$

Answer

Correct option: B.
$M\,{n^2}{R^2}{t^2}$
b
Centripetel acceleration ${a_c} = {n^2}R{t^2}$

$\begin{gathered}
  {a_c} = \frac{{{v^2}}}{R} = {n^2}R{t^2} \hfill \\
  {v^2} = {n^2}{R^2}{t^2} \hfill \\ 
\end{gathered} $

$v = nRt$

${a_c} = \,\frac{{dv}}{{dt}} = nR$

Power $= M{a_c}v = MnRnRt = M{n^2}{R^2}t.$

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