A body starts from rest and moves with a uniform acceleration of  20 m/s² in the first 10s. During the next 10s it moves with the maximum velocity attained uniformly. The total displacement of the body is

Given that  $u=0$
 $a=20m/s^2$
$t=10S$
Step-I
From kinematic equation of motion  $S=ut+\frac{1}{2}a{t}^2$
$\Rightarrow S=0+\frac{1}{2}\times 20\times 100$ 
$=1000m\mathrm{.............}\left(1\right)$   
The maximum velocity attained is
$V=\frac{ds}{dt}C=$  
$=0+20\times 10=200m/s$  
Step-II
$\therefore$ During the next  10S, the displacement covered with uniform velocity of 200 m/s is 
  $S=Vt$
  $=200\times 10=2000m\mathrm{.........}\left(2\right)$
$\therefore$ The total displacement of the body covered 
  $S=1000+2000$
  $=3000m$