Final answer:
To calculate the time for a rocket to reach 400 m/s with a 20 m/s² acceleration, use the equation t = (´v - vo) / a, which gives us 20 seconds.
Step-by-step explanation:
Understanding Motion and Acceleration:
To find the time it takes for a rocket to reach a velocity of 400 m/s when it accelerates at a rate of 20 m/s², you can use the equation v = vo + at. Here, 'v' is the final velocity, 'vo' is the initial velocity, which is 0 m/s since the rocket starts from rest, 'a' is the acceleration, and 't' is the time. By rearranging the equation to solve for 't', we get:
t = ´(v - vo) / a
Plugging in the given values:
t = (400 m/s - 0 m/s) / (20 m/s²) = 20 seconds
So, it takes 20 seconds for the rocket to reach the velocity of 400 m/s.