How to Solve an Integral Using Leibniz Rule of Integration?

[GhostSpirit]

How can I apply Leibniz rule of integration to solve the integral
$$\int_0^t{f\left(t\right)\dot{a}^2\left(t\right)dt}$$
I want to get rid of $$\dot{a}$$??

 

[GhostSpirit]

I am sorry, I meant I want to get rid of $$\dot{a}^2$$. Is there any answer to solve this integral? I can have $$\dot{f}$$ in the answer.

Thanks,