The flight time refers to the total amount of time the ball is in the air, from just after it is launched () until just before it lands (). Hence the flight time can be calculated as , or just in this particular situation since . Because the ball lands at the same height from which it was launched, by symmetry it spends half its flight time traveling up to the peak and the other half traveling back down. The flight time is determined by the initial vertical component of the velocity and by the acceleration. The flight time does not depend on whether the object is moving horizontally while it is in the air.