Two objects are located at height $10\,\text{m}$ above the ground. At some point of time, the objects are thrown with initial velocity $2\sqrt{2}\,\text{m/s}$ at an angle $45^\circ$ and $135^\circ$ with the positive X-axis respectively. Assuming $g = 10\,\text{m/s}^2$, the velocity vectors will be perpendicular to each other at time equal to