Respuesta :

Let u = upward initial speed of the flea.

At the maximum height of h = 0.550 m, the vertical velocity is v = 0.
Therefore, from the formula
 v² = u² - 2gh,
obtain
0 = u² - 2*(9.8 m/s²)*(0.55 m) 
u² = 10.78 m²/s²
 u = 3.283 m/s

Answer: The initial upward speed is 3.28 m/s (nearest thousandth)