Answer:
8 m/s^2
Explanation:
F=kA
F=force
k=constant you will use for each F=kA relation
A=acceleration
Second sentence says F=90 while A=10 (plug in and find k)
90=k(10) so k=9
We have for any (A,F) that F=9A
Last sentence F=72, what is A?
So 72=9A which means A=8 m/s^2