Question

The figure shows the v-t graph of a particle moving in straight line . Find the time when particle returns to the starting points.

Answer 1

$\int dx=0$

$\Rightarrow \int vdt=0$

$\Rightarrow \frac{1}{2}\times 25\times 20-\frac{1}{2}(t-25)\times 4(t-25)=0$

$\Rightarrow 4(t-25{)}^2={50}^o$

$\Rightarrow 2(t-25)=10\sqrt{5}$

$\Rightarrow t=25+5\sqrt{5}$