[tex]\Huge{\underline{\underline{\mathfrak{Answer \colon}}}}[/tex]
According to the Question,
[tex] \large{\sf{ f \propto \: a}}[/tex]
Force exerted on the object at a = 9 m/s²
We Know that,
[tex] \huge{\boxed{ \boxed{ \sf{f = ma}}}}[/tex]
Firstly,we need to find the mass of the object
Thus,
[tex] \sf{m = \frac{f}{a} } \\ \\ \implies \: \sf{m = \frac{25}{5} } \\ \\ \huge{ \implies \: \sf{m = 5 \: kg}}[/tex]
Now,
[tex] \sf{F = mA} \\ \\ \implies \: \sf{F = (5)(9)} \\ \\ \huge{ \implies \: \sf{F = 45 \: N}}[/tex]