Answer:
800 meters
Explanation:
To do this, we can use this formula:
v^2 = u^2 + 2as
where v is the final velocity (0 m/s), u is the initial velocity (40 m/s), a is the acceleration (-2 m/s^2), and s is the distance covered (400 m).
Plugging in the values, we get:
0^2 = 40^2 + 2(-2)s
Simplifying this equation, we get:
s = 800 meters
Since the platform is only 400 meters long, the train will not be able to come to a complete stop in time.
