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JEE Main 202429 JanuaryEvening Shift
Exam
JEE Main
Year
2024
Date
29 January
Shift
Evening Shift
Subject
Physics
Chapter
Laws of Motion

JEE Main 2024 · 29 January · Evening Shift · Physics · Laws of Motion

A particle is moving in a circle of radius 50cm in such a way that...

A particle is moving in a circle of radius 50cm50cm in such a way that at any instant the normal and tangential components of its acceleration are equal. If its speed at t=0t = 0 is 4ms−14m{s}^{- 1}, the time taken to complete the first revolution will be 1α[1−e−2π]s\dfrac{1}{\alpha}\left[1 - {e}^{- 2\pi}\right]s, where α=\alpha =______.

Correct answer

0

Step-by-step solution

Given:

∣a→c∣=∣a→t∣\left|\overset{\to}{a}c\right| = \left|\overset{\to}{a}t\right|

⇒v2r=dvdt⇒ \dfrac{{v}^{2}}{r} = \dfrac{dv}{dt}

⇒∫4vdvv2=∫0tdtr⇒ {∫}_{4}^{v}\dfrac{dv}{{v}^{2}} = {∫}_{0}^{t}\dfrac{dt}{r}

⇒[−1v]4v=tr⇒ {\left[\dfrac{- 1}{v}\right]}_{4}^{v} = \dfrac{t}{r}

⇒−1v+14=2t⇒ \dfrac{- 1}{v} + \dfrac{1}{4} = 2t

⇒v=41−8t=dsdt⇒ v = \dfrac{4}{1 - 8t} = \dfrac{ds}{dt}

⇒4∫0tdt1−8t=∫0sds⇒ 4{∫}_{0}^{t}\dfrac{dt}{1 - 8t} = {∫}_{0}^{s}ds

\left(r = 0 . 5m, \text{distance}\text{covered}s = 2\pir = \pi\right)</p><p></p><p>⇒ 4 \times \dfrac{[ \ln ( 1 - 8t ) {]}_{0}^{t}}{- 8} = \pi</p><p></p><p>⇒ ℓn ( 1 - 8t ) = - 2\pi</p><p></p><p>⇒ 1 - 8t = {e}^{- 2\pi}</p><p></p><p>⇒ t = \left(1 - {e}^{- 2\pi}\right)\dfrac{1}{8}s</p><p>So,</p><p>So,\alpha = 8$.

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