Explanation:
initial velocity(u) = 90 km/s = 25 m/s
time (t) = 5 sec
mass (m) = 200 kg
final velocity (v) = 0 m/s
v = u + at
0 = 25 + a * 5
-25 = 5 a
-5 = a
Therefore acceleration = -5m/s²
Force = mass * acceleration
F = 200*-5
F = -1000 N
