Answer:
a= 9.81 s
Step-by-step explanation:
vi= 8m/s
a= -9.81 m/s
d= 640m
t= 40s
1. Find final velocity
vf= vi +a(t)
vf= 8m/s + -9.81m/s x 40s
vf = -384.4 m/s
acceleration= change in velocity/ change in time
a= -384.4- 8= -392.4/ 40s = 9.81s
a= 9.81 m/s
Hopefully this helps and is correct! Much love ❤️