a flea jump up

(a) Use equation of motion: v^2 = u^2 + 2a.s
with v = 0 m/s, a = -g(= -9.81 m/s^2), s = 0.44 m, u =?
hence, 0 = u^2 + 2.(-9.81).(0.44)
u = 2.94 m/s

The initial jumping speed of the flea is 2.94 m/s.

(b) Use equation of motion: s = ut + (1/2)at^2
with s = 0 m, u = 2.94 m/s, a = -g(=-9.81 m/s^2), t=?
Hence, 0 = 2.94t + (1/2).(-9.81)t^2
t = 2.94 x 2/9.81 s = 0.6 s

The time for the flea in air is 0.6 s