Please read this paragraph...... I had a doubt in the part I marked. How can we use integral calculus to find the force exerted by a uniform rod placed on its perpendicular bisector? Plz explain with a diagram too.

Further, the techniques of mathematics such as algebra, trigonometry and calculus can be used to make predictions from the basic equations. Thus, if we know the basic rule (1.1) about the force between two particles, we can use the technique of integral calculus to find what will be the force exerted by a uniform rod on a particle placed on its perpendicular bisector.