Center of gravity of a body is an imaginary point at which the body's gravitational force effectively acts. It helps to predict a moving object's behavior under gravity and design static structures such as buildings and bridges. To understand it better, consider balancing a basketball on a forefinger. The basketball placed on the forefinger experiences a gravitational force at the center of gravity in the downward direction. If the center of gravity of the basketball lies on the axis that passes through the finger, the gravitational force is countered by the normal force balancing the basketball on the finger. If the basketball slightly moves from the equilibrium position, the center of gravity of the basketball shifts outside the axis line of the finger. As a result, the torque due to its weight acts at this point, and the basketball topples.