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JEE MAIN 2021
26-02-2021 S1
Question
A particle is moving with uniform speed along the circumference of a circle of radius R under the action of a central fictitious force F which is inversely proportional to $\mathrm{R}_3$. Its time period of revolution will be given by :
Select the correct option:
A
$\mathrm{T} \propto \mathrm{R}^2$
B
$T \propto R^{\frac{3}{2}}$
C
$T \propto R^{\frac{5}{2}}$
D
$T \propto R^{\frac{4}{3}}$
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
$\begin{aligned} & F \propto \frac{1}{R^3} \\ & \frac{K}{R^3}=m \omega^2 R \\ & \omega^2=\frac{K}{m} \times \frac{1}{R^4} \\ & \left(\frac{2 \pi}{T}\right)^2=\frac{K}{m} \times \frac{1}{R^4} \\ & T^2 \propto R^4 \\ & T \propto R^2\end{aligned}$
Question Tags
JEE Main
Physics
Easy
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