Respuesta :

saraharif006

Answer:

Step-by-step explanation:

acceleration, a = 20 m/s^2

initial velocity, u = 0 since it starts from rest

final velocity, v = 400 m/s

v = u + at

400 = 0 + 20 t

400 = 20 t

t = 400 / 20

t = 20 sec

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