Question

HLOO MATES ,Answer fast guys​

Answer 1

Let the total time taken by the body during which the average velocity becomes $\displaystyle\sf {30\ m\,s^{-1}}$ be $\displaystyle\sf {t.}$

Given that the velocity of the body is changed through $\displaystyle\sf {30\ m\,s^{-1}}$ during this time. It means the final velocity attained by the body after this time is 30 more than the initial one due to the acceleration, $\displaystyle\sf {a=3\ m\,s^{-2}.}$

Hence the final velocity is,

$\displaystyle\longrightarrow\sf{v=u+30}$

By first equation of motion,

$\displaystyle\longrightarrow\sf{u+3t=u+30}$

$\displaystyle\longrightarrow\sf{3t=30}$

$\displaystyle\longrightarrow\sf{t=10\ s}$

Now, the total distance covered by the body during this 10 seconds is given by,

$\displaystyle\longrightarrow\sf{Total\ Distance=Average\ Velocity\times Total\ Time}$

Given, the average velocity is $\displaystyle\sf {30\ m\,s^{-1}.}$ Then,

$\displaystyle\longrightarrow\sf{s=30\times10}$

$\displaystyle\longrightarrow\sf {\underline {\underline {s=300\ m}}}$

Hence 300 m is the answer.