Download App

STD 11 - 2. motion in straight line — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 11 - 2. motion in straight line4 Marks
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 $x=3 u$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "SECTION - A [PHYSICS MCQ]" from STD 11 - 2. motion in straight line→STD 11 - 2. motion in straight line — all question types→JEE STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

A TV transmission tower antenna is at a height of $20\, m$. Suppose that the receiving antenna is at.

$(i)$ ground level

$(ii)$ a height of $5 \,m$.

The increase in antenna range in case $(ii)$ relative to case $(i)$ is $n \%$.

The value of $n$, to the nearest integer, is .....$\%$

→
A photon of wavelength $\lambda$ is absorbed by an electron confined to a box of length $\sqrt{(35 h \lambda / 8 m c)}$. As a result, the electron makes a transition from state $k=1$ to the state $n$. Subsequently the electron transist from the state $n$ to the state $m$ by emitting a photon of wavelength $\lambda^{\prime}=1.75 \lambda$. Then,
→
In an ac generator, a rectangular coil of $100$ turns each having area $14 \times 10^{-2}\,m ^2$ is rotated at $360\,rev / min$ about an axis perpendicular to a uniform magnetic field of magnitude $3.0 T$. The maximum value of the emf produced will be $............V$. $\left(\right.$ Take $\left.\pi=\frac{22}{7}\right)$
→
${H^ + },\,H{e^ + }$ and ${O^{ + + }}$ ions having same kinetic energy pass through a region of space filled with uniform magnetic field $B$ directed perpendicular to the velocity of ions. The masses of the ions ${H^ + },\,H{e^ + }$and ${O^{ + + }}$ are respectively in the ratio $1:4:16$. As a result
→
Self inductance of solenoid is $'L'$ which is made by a wire of length $'l_w'$ then length  of solenoid is
→
The cut-in voltage for silicon diode is approximately.....$V$
→
Two electric bulbs marked $25\ W - 220\ V$ and $100\ W - 220\ V$ are connected in series to a $440\ V$ supply. Which of the bulbs will fuse?
→
Which of the following equations is dimensionally incorrect?

Where $t=$ time, $h=$ height, $s=$ surface tension, $\theta=$ angle, $\rho=$ density, $a, r=$ radius, $g=$ acceleration due to gravity, ${v}=$ volume, ${p}=$ pressure, ${W}=$ work done, $\Gamma=$ torque, $\varepsilon=$ permittivity, ${E}=$ electric field, ${J}=$ current density, ${L}=$ length.

→
Image
→
Consider a point $P$ on the circumference of a disc rolling along a horizontal surface. If $R$ is the radius of the disc, the distance through which $P$ moves in one full rotation of the disc  is:
→