物理題目一問(力和運動)

Use equation of motion: s = ut + (1/2)at^2
with u = 0 m/s, a = g(= 10 m/s^2), t = 1 s, s =?
Hence, s = (1/2).(10)(1^2) m = 5 m
The stone travels 5 m in the first second.

Use the equation again with t = 2 s,
s = (1/2).(10)(2^2) m = 20 m
The stone thus travels 20 m in the first two seconds.
Hence, distance travelled in the second second (第二秒) = (20 - 5) m = 15 m

Therefore, ratio of distances travelled = 5/15 = 1/3 = 1:3