中三物理的問題（急！！）

Your calculations to the two questions are right.

In Q1, you may use a suuplementary equation of motion in case the initial velocity u is unknown. The quation is,

s = vt - (1/2)a.t^2

In Q1, we have v = 0 m/s, a = -10 m/s2, s = 1/2 s, s = ?
hence, s = -(1/2)(-10)(0.5)^2 m = 1.25 m