A particle of mass $m$ is under an influence of a force $\mathbf{F}=\left(-k \mathbf{x}+\mathbf{F}_0\right)…

A particle of mass $m$ is under an influence of a force $\mathbf{F}=\left(-k \mathbf{x}+\mathbf{F}_0\right) \mathrm{N}$. The particle when disturbed will oscillate
  1. about $x=0$ with $\omega=\sqrt{\frac{k}{m}}$
  2. about $x=0$ with $\omega=\sqrt{\frac{m}{k}}$
  3. about $x=\frac{F_0}{k}$ with $\omega=\sqrt{\frac{k}{m}}$
  4. about $x=\frac{F_0}{k}$ with $\omega \neq \sqrt{\frac{k}{m}}$

Solution

Given that, Mass of particle $=m$ Restoring force, $\mathbf{F}=\left(-k \mathbf{x}+\mathbf{F}_0\right) \mathrm{N}$ $\begin{aligned} & =-k\left(x-\frac{\mathbf{F}_0}{k}\right) \\ & =-k y \quad\left[\text { Take, } x-\frac{\mathbf{F}_0}{k}=y\right]\end{aligned}$ Which is SHM. We know that, at the mean position, $y=0$ $x-\frac{\mathbf{F}_0}{k}=0 \Rightarrow x=\frac{\mathbf{F}_0}{k}$ $\therefore \quad F=m a \Rightarrow m a=-k y$ $m\left(-\omega^2 y\right)=-k y \Rightarrow \omega=\sqrt{\frac{k}{m}}$ Frequency of SHM, $\omega=\sqrt{\frac{k}{m}}$

Asked in: AP EAMCET 2021 (23 Aug Shift 2)

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