According to the Question,
![\large{\sf{ f \propto \: a}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5u9chkl63zja6tq408qsc4q48w2jwsgv8u.png)
From the Question,
- Initial Acceleration,a = 5 m/s²
- Force at a = 5 m/s²,f = 25 N
- Final Acceleration,A = 9 m/s²
To find
Force exerted on the object at a = 9 m/s²
We Know that,
![\huge{\boxed{ \boxed{ \sf{f = ma}}}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/a0r8h9u10gomoy0iy2wpcipx7jvcwg33rb.png)
Firstly,we need to find the mass of the object
Thus,
![\sf{m = (f)/(a) } \\ \\ \implies \: \sf{m = (25)/(5) } \\ \\ \huge{ \implies \: \sf{m = 5 \: kg}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3l4wfsflv5yiqc48it3ihzs61ukilq72cx.png)
Now,
![\sf{F = mA} \\ \\ \implies \: \sf{F = (5)(9)} \\ \\ \huge{ \implies \: \sf{F = 45 \: N}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/nw5qkdhwqdaskimru3cz5ids6km5gv66hr.png)