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2. motion in straight line — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics2. motion in straight line1 Mark
MCQ
Two trains are moving with equal speed in opposite directions along two parallel railway tracks. If the wind is blowing with speed $u$ along the track so that the relative velocities of the trains with respect to the wind are in the ratio of $1:2$, then the speed of each train must be
  • ✓
    $3u$
  • B
    $2u$
  • C
    $4u$
  • D
    $u$
✓

Answer

Correct option: A.
$3u$
a
Let the speed of trains be $x$

$\therefore \frac{x-u}{x+u}=\frac{1}{2}$ or $2 x-2 u=x+u$

or $x=3 u$

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