Answer
(a) v = 2.94 m/s
(b) t = 0.600 s
Work Step by Step
(a) When the flea reaches its maximum height, then the velocity v = 0 m/s.
$v^2 = v_0^2 + 2ay$
$v_0^2 = 0 - 2ay$
$v_0 = \sqrt{-2ay} = \sqrt{-(2)(-9.80 ~m/s^2)(0.440 ~m)}$
$v_0 = 2.94~m/s$
(b) We can find the time $t$ to reach maximum height.
$t = \frac{v-v_0}{a} = \frac{0-2.94~m/s}{-9.80~m/s^2}$
$t = 0.300~s$
The total time in the air is 2t = (2)(0.300 s), which is 0.600 seconds.
