આકૃતિમાં બતાવ્યા પ્રમાણે અવગણ્ય આડછેદનું ક્ષેત્રફળ ધરાવતા એક અસંમિત સમાન ચોસલાનું દ્રવ્યમાન કેન્દ્ર \(\vec r\, cm\) ______ હશે.

A \(\vec r\,cm = \frac{{13}}{8}L\hat x + \frac{5}{8}L\hat y\)
B \(\vec r\,cm = \frac{{5}}{8}L\hat x + \frac{13}{8}L\hat y\)
C \(\vec r\,cm = \frac{{3}}{8}L\hat x + \frac{11}{8}L\hat y\)
D \(\vec r\,cm = \frac{{11}}{8}L\hat x + \frac{3}{8}L\hat y\)

Verified Solution

Answer & Solution

Correct Answer

(A) \(\vec r\,cm = \frac{{13}}{8}L\hat x + \frac{5}{8}L\hat y\)

Step-by-step Solution

Detailed explanation

Three parts of rod can be considered as point masses. \({\overrightarrow r _{cm}} = \frac{{2m\,{{\overrightarrow r }_1} + m{{\overrightarrow r }_2} + m{{\overrightarrow r }_3}}}{{4\,m}}\)…

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.

Same subject

સૂચી \(-I\) ને સૂચી \(- II\) સાથે મેળવો.

સૂચી \(-I\)	સૂચી \(-II\)
\((a)\) \(h\) (પ્લાન્કનો અચળાંક)	\((i)\) \(\left[ M L T ^{-1}\right]\)
\((b)\) \(E\) (ગતિ ઊર્જા)	\((ii)\) \(\left[ M L ^{2} T ^{-1}\right]\)
\((c)\) \(V\) (વિદ્યુત સ્થિતિમાન)	\((iii)\) \(\left[ M L ^{2} T ^{-2}\right]\)
\((d)\) \(P\) (રેખીય વેગમાન)	\(( iv )\left[ M L ^{2} I ^{-1} T ^{-3}\right]\)

નીચે આપેલા વિકલ્પોમાંથી સાચા જવાબનું ચયન કરો.

JEE Mains 2021 Medium

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