①
s1 = 1/2 * g * t1^2 = 1/2*10*10^2 = 500 (m)
s2 = s - s1 = 1118 - 500 = 618 (m)
v1 = g * t1 = 10*10 = 100(m/s)
a = (v1^2 - v2^2)/(2*s2) = (100^2 - 4^2)/(2*618) = 7.26861(m^2/s)
②
設(shè) 離開飛機(jī)后t(s)內(nèi)拉開降落傘
則
s1 = 1/2 * g * t^2
s2 = s - s1
v1 = g*t
(v1^2 - v2^2)/(2*s2) = 4
帶入 有 [(g*t)^2 - 4^2]/[2*(s - 1/2*g*t^2)] = 4
其中 g = 10 (m^2/s)
s = 1118 (m)
公式都正確 你慢慢算吧 睡覺去了