A car covers A B distance with first one-third at velocity v _ 1 … - Vidyadip

MCQ

A car covers $A B$ distance with first one-third at velocity $v _{1} ms ^{-1}$, second one-third at $v _{2} ms ^{-1}$ and last one-third at $v _{3} ms ^{-1}$. If $v _{3}=3 v _{1}, v _{2}=2 v _{1}$ and $v _{1}=11\,ms ^{-1}$ then the average velocity of the car is________ $ms ^{-1} .$

A
$17$
B
$16$
C
$20$
✓
$18$

✓

Answer

Correct option: D.

$18$

d
$\langle\overrightarrow{ v }\rangle=\frac{\text { Displacement }}{\text { time }}$

(Let displacement be $l$ )

$=\frac{\ell}{\left(\frac{\ell}{ V _{3}}+\frac{\ell}{ V _{2}}+\frac{\ell}{ V _{1}}\right) \frac{1}{3}}$

$=\frac{3}{\frac{1}{ V _{1}}+\frac{1}{ V _{2}}+\frac{1}{ V _{3}}}=\frac{3}{\frac{1}{11}+\frac{1}{22}+\frac{1}{33}}$

$=18\,m / s$

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

NEET STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Figure represents a graph of kinetic energy $(K)$ of photoelectrons (in $eV$) and frequency $(v)$ for a metal used as cathode in photoelectric experiment. The work function of metal is ............. $eV$

The dimension of $P = \frac{{{B^2}{l^2}}}{m}$ is

where $B=$ magnetic field, $l=$ length, $m =$ mass

In a $YDSE$ apparatus, two identical slits are separated by $1\, mm$ and distance between slits and screen is $1\, m$. The wavelength of light used is $6000\, Å$. The minimum distance between two points on the screen having $75\%$ intensity of the maximum intensity is ......$mm$

Two coils have a mutual inductance $0.005\,H$ . The current changes in the first coil The current changes in the first coil according to the equation $I = I_0 sin\,\omega t$ , where $I_0 = 10\,A$ and $\omega = 100\pi \,rad/s$ . The maximum value of $emf$ in the second coil will be

Acetophenone is prepared by the reaction of which of the following in the presence of $AlC{l_3}$ catalyst

In the circuit, if the forward voltage drop for the diode is $0.5\, V$, the current will be.......$mA$

An object is dropped from a height $h$ from the ground. Every time it hits the ground it looses $50\%$ of its kinetic energy. The total distance covered as $t \to \infty $ is

A wire of diameter $0.02\,meter$ contains $10^{28}$ free electrons per cubic meter. For an electrical current of $100\, A$, the drift velocity of the free electrons in the wire is nearly

Two identical satellites are at $R$ and $7R$ away from earth surface, the wrong statement is ($R $ = Radius of earth)

A train is running at a constant speed of $90 \,km / h$ on a straight track. A person standing at the top of a boggey moves in the direction of motion of the train such that he covers 1 meters on the train each second. The speed of the person with respect to ground is .........