A lizard, at an initial distance of 21 ~cm behind an insect, moves from rest with an acceleration of 2 ~cm / s^2 and pursues the insect which is crawling uniformly along a straight line at a speed of 20 ~cm / s . Then

Correct answer: C. 21 ~s aligned & (1)/(2)2 t²=21+20 t & t=21 . aligned

JEE Main 2005

Exam: JEE Main
Year: 2005
Subject: Mathematics
Chapter: Heights and Distances

JEE Main 2005 · Mathematics · Heights and Distances

A lizard, at an initial distance of 21 ~cm behind an insect, moves...

A lizard, at an initial distance of

21 \mathrm{~cm}

behind an insect, moves from rest with an acceleration of

2 \mathrm{~cm} / \mathrm{s}^2

and pursues the insect which is crawling uniformly along a straight line at a speed of

20 \mathrm{~cm} / \mathrm{s}

. Then the lizard will catch the insect after

Options

A $20 \mathrm{~s}$
B $1 \mathrm{~s}$
C $21 \mathrm{~s}$
D $24 \mathrm{~s}$

Correct answer

C. $21 \mathrm{~s}$

Step-by-step solution

\begin{aligned}& \frac{1}{2}2 t²=21+20 t \\ & \Rightarrow t=21 . \end{aligned}

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