Given,
The range of the projectile, R=43.0 m
The angle at which the bucket is projected, θ=72.0°
The range of a projectile is the maximum displacement of the projectile in the x-direction.
And the range is given by,
Where u is the initial velocity and g is the acceleration due to gravity.
On substituting the known values,
Thus the initial velocity must be 26.77 m/s