Answer:
about -1.26 m/s²
Step-by-step explanation:
The acceleration can be found from the formula ...
a = (v2² -v1²)/(2d)
Here, we have the initial velocity v1=23 m/s, the final velocity v2=0, and teh distance d=210 m. Using the formula, we find the acceleration to be ...
a = (0 -23²)/2(210) ≈ -1.2595 . . . m/s²