The snowball travels a horizontal distance x and has height y at time t according to
x = vt
y = 0.9 m - 1/2 gt ²
where g = 9.8 m/s² is the magnitude of the acceleration due to gravity.
Set y = 0 and solve for t :
0 = 0.9 m - 1/2 gt ²
t ² = (1.8 m) / g
t ≈ 0.43 s
The target is 2 m away from where the snowball is thrown, so it was thrown with speed v such that
2 m = v (0.429 s)
v = (2 m) / (0.43 s)
v ≈ 4.7 m/s
