MHT CET · Physics · Oscillations

A body is executing S.H.M. under the action of force having maximum magnitude \(50 \mathrm{~N}\). When its energy is half kinetic and half potential, the magnitude of the force acting on the particle is

A \(\frac{25}{\sqrt{2}} \mathrm{~N}\)
B \(50 \mathrm{~N}\)
C \(25 \mathrm{~N}\)
D \(25 \sqrt{2} \mathrm{~N}\)

Verified Solution

Answer & Solution

Correct Answer

(D) \(25 \sqrt{2} \mathrm{~N}\)

Step-by-step Solution

Detailed explanation

Potential energy is a half of the total energy
\(
\begin{aligned}
& \therefore \frac{1}{2} \mathrm{~m} \omega^2 \mathrm{x}^2=\frac{1}{2}\left[\frac{1}{2} \mathrm{~m} \omega^2 \mathrm{~A}^2\right] \\
& \therefore \mathrm{x}^2=\frac{\mathrm{A}^2}{2} \text { or } \mathrm{x}=\frac{\mathrm{A}}{\sqrt{2}}
\end{aligned}
\)
Maximum force \(F_m=m \omega^2 A\)
Force at a distance \(\mathrm{x}, \mathrm{F}^{\prime}=\mathrm{m} \omega^2 \mathrm{x}\)
\(
\begin{aligned}
& \therefore \frac{F^{\prime}}{F_m}=\frac{x}{A}=\frac{1}{\sqrt{2}} \\
& \therefore F^{\prime}=\frac{F_m}{\sqrt{2}}=\frac{50}{\sqrt{2}}=25 \sqrt{2} N
\end{aligned}
\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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