Answer:
68m/s
Explanation:
Given parameters:
Mass = 30g  = 0.03kg
Potential energy  = 70J
Unknown:
Velocity  = ?
Solution;
Since there is no loss in energy, the potential energy and kinetic energy will be the same when shot;
       P.E = K.E
      K.E  =  P.E  = [tex]\frac{1}{2}[/tex] m v²
            70 = [tex]\frac{1}{2}[/tex]  x 0.03 x v² Â
             70 = 0.015v²
              v = 68m/s