Easy MCQ +4 / -1 PYQ · JEE Mains 2022

Two buses P and Q start from a point at the same time and move in a straight line and their positions are represented by ${X_P}(t) = \alpha t + \beta {t^2}$ and ${X_Q}(t) = ft - {t^2}$. At what time, both the buses have same velocity?

  1. A ${{\alpha - f} \over {1 + \beta }}$
  2. B ${{\alpha + f} \over {2(\beta - 1)}}$
  3. C ${{\alpha + f} \over {2(1 + \beta )}}$
  4. D ${{f - \alpha } \over {2(1 + \beta )}}$ Correct answer

Solution

<p>${X_P} = \alpha t + \beta {t^2}$</p> <p>${X_Q} = ft - {t^2}$</p> <p>$\therefore$ ${V_P} = \alpha + 2\beta t$</p> <p>${V_Q} = f - 2t$</p> <p>$\because$ ${V_P} = {V_Q}$</p> <p>$\Rightarrow \alpha + 2\beta t = f - 2t$</p> <p>$\Rightarrow t = {{f - \alpha } \over {2(1 + \beta )}}$</p>

About this question

Subject: Physics · Chapter: Kinematics · Topic: Motion in a Straight Line

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