The displacement of a body along x-axis depends on time as$\sqrt{\mathrm{x}}=\mathrm{t}+1$ .  Then the velocity of body after 2 sec. in metre/sec is

$\sqrt{\mathrm{x}}=\mathrm{t}+1$
Squaring both sides, we get,
$\mathrm{x}={(\mathrm{t}+1)}^2={\mathrm{t}}^2+2\mathrm{t}+1$
Differentiating it w.r.t. time t, we get,
$\frac{\mathrm{dx}}{\mathrm{dt}}=2\mathrm{t}+2$
Velocity, u = $\frac{\mathrm{dx}}{\mathrm{dt}}=2\mathrm{t}+2$= 4 + 2 = 6.