S1 = a (t2+20c)^2/2S2 = at^2/2
S1 - S2 = 240m0.4 (t+20)^2/2 - 0.4t^2/2 = 2400.2 (t^2 + 20t + 400) - 0.2t^2 = 2400.2t^2 + 4t + 80 - 0.2t^2 = 2404t = 240 -804t =160t = 40 секунд
S1 = a (t2+20c)^2/2
S2 = at^2/2
S1 - S2 = 240m
0.4 (t+20)^2/2 - 0.4t^2/2 = 240
0.2 (t^2 + 20t + 400) - 0.2t^2 = 240
0.2t^2 + 4t + 80 - 0.2t^2 = 240
4t = 240 -80
4t =160
t = 40 секунд