In this problem, we assume that the projectile was sent vertically upward. The maximum height reached is calculated through the equation,
H = (v²sin²θ)/2g
where H is the maximum height, v is the velocity, θ is the angle (in this case, 90 degrees) and g is the gravitational constant.
Substituting the known values from the given,
2.1 = (v²)(1) / (2 x 9.8)
v = 6.415 m/s
Thus, the initial sped of the projectile is approximately equal to 6.42 m/s.
