Answer
$21.0\frac{m}{s}$
Work Step by Step
The initial speed of the second ball can be determined as follows:
$v_y=v_{\circ}sin\theta-gt$
$\implies -(v_{\circ}sin\theta)=v_{\circ}sin\theta-gt$
This can be rearranged as:
$v_{\circ}=\frac{gt}{2sin\theta}$
We plug in the known values to obtain:
$v_{\circ}=\frac{(9.81)(2.75)}{2sin40.0^{\circ}}$
$v_{\circ}=21.0\frac{m}{s}$
