Calvin's Parachute

An aeroplane was moving horizontally when a parachute bailed out of the plane at a height $55\omega^{2}$ (in metres) from the ground, where $\omega$ is the time after which the parachute is opened after bailing out. Find the decelaration so that Calvin reached the ground with zero velocity.

Take $(g=10\text{ m/s}^{2})$ .