A dynamite blast sends a piece of rock (shatter) straight upwards. After 2.31x10^0 s the piece of rock has a velocity of 1.56x10^1 m/s. Assuming there is no air resistance, what is the initial velocity of the rock, to two significant figures?

V(t) = Vo - g*t

Solve for Vo, knowing that V(t) = 15.6 m/s when t = 2.31 s. Use g = 9.81 m/s^2
Vo = 15.6 + 9.81*2.31 = ___

You do the math.