I got 6000N as my answer.
Step-by-step explanation:
m = 1200
v = 30m/s
u = 0m/s
p = 90kW : 90,000W
½m(v²-u²)
½ x 1200(30 x 30 - 0)
½ x 1200 x 900
½ x 1080000 = 540000j
p = e/t : t = e/p
t = 540000/90000
t = 6secs
a = v/t
a = 30/6
a = 5
F = ma
F = 1200 x 5
F = 6000N