A stone is thrown vertically up from the top end of a window of height 1.8 m with a velocity of $8 \mathrm{~ms}^{-1}$. The time taken by the stone to cross the window during its downward journey is (acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

A body is falling freely from the top of a tower of height 125 m . The distance covered by the body during the last second of its motion is $x \%$ of the height of the tower. Then, $x$ is (Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

The displacement-time graphs of two moving particles make angles of $30^{\circ}$ and $45^{\circ}$ with the time axis. The ratio of their velocities is

The acceleration of a vertically projected body at its highest reaching position is