If we are supposed to assume that the gain in potential energy is equal to the loss in kinetic energy then:
m g h = (1/2)m (V1^2-V2^2)
which is approximately
g h = (1/2)(V1+V2)(V1-V2)
if V is much greater than 100m/s then V1+V2 is about 2 V where V is the starting speed
so
g h = (1/2)(2 V)(100)
h = (100 V/9.81)
so of course I need V
find the altitude change of a 10000-kg fighter which clims and in so doing, loses 100 m/s of airspeed
2 answers
The gain in PE equals the loss of KE only if there is no thrust. That is no way to fly a fighter jet, unless it is doing a zero-g maneuver.