Final answer:
The car's velocity at point 'A' cannot be determined without the displacement value. To calculate it, we would apply the kinematic equation that relates initial velocity, final velocity, acceleration, and displacement, assuming constant acceleration.
Step-by-step explanation:
To find the car's velocity at point 'A', we will use the kinematic equation that relates initial velocity, final velocity, acceleration and displacement:
vf^2 = vi^2 + 2aΔx
Where vf is the final velocity, vi is the initial velocity, a is the acceleration, and Δx is the displacement. Given that the final velocity (vf) is 21 m/s, the acceleration (a) is 0.853 m/s², but we are not given the displacement directly. To proceed, we'll assume the word 'meters' late in the question refers to either a typo or an omitted displacement value which we would need to know to solve the problem.
Assuming that we had the displacement, we could then rearrange the equation to solve for the initial velocity (vi):
vi = sqrt(vf^2 - 2aΔx)
Without the displacement value, we cannot calculate the car's velocity at point 'A'. More information is needed to provide an accurate answer.