We are given that
Case - I:
when t = 0, u = 0 when t = 8 sec, v = ?
Acceleration (a) = 5 m/s2
∴ v = u + at
= 0 + 5 x 8 = 40 m/s
s = ut + \(\frac{1}{2}\) at2
s = 0 + \(\frac{1}{2}\) x 5 x (8)2 = \(\frac{1}{2}\) x 5 x 64 = 160m
Case-II: t = 8 sec to t = 12 sec.
Distance = speed x time
= 40 x 4 = 160 m.
So, the total distance travelled
= 160 + 160 = 320 m.