Question

The stone is thrown upward with an initial velocity of 100m/s What is the velocity of the ball after 2 seconds.

Answer 1

v = v_₀ - gt
so plug in your numbers

Answer 2

a = g = -9.81 m/s^2 on earth more or less
v = Vinitial + g t = Vi - 9.81 t
h = Height initial + Vi t + (a/2) t^2 = 0 + 100 t - 4.9 t^2
it t = 2
v = 100 - 9.81 * 2 = 100 - 19.6 = 80.4 m/s