To find the time taken to accelerate from rest to a certain speed when you know the final velocity and acceleration, you can use the following equation:
t = (v - u) / a
where: t is the time taken to accelerate (in seconds), v is the final velocity (in meters per second), u is the initial velocity (in this case, since you're starting from rest, u = 0), and a is the acceleration (in meters per second squared).
By substituting the given values into the equation, you can calculate the time taken to accelerate.