Here's why:

* Torque: Torque is the rotational equivalent of force. It's a force that causes an object to rotate around an axis.

* Center of Mass: The center of mass is the point where all the mass of an object can be considered to be concentrated.

When a force acts through the center of mass, it doesn't create any torque because:

* The force vector and the distance vector (from the axis of rotation to the point of force application) are parallel.

* The sine of the angle between these two vectors is zero (sin 0° = 0).

* Torque is calculated as the cross product of the force vector and the distance vector, and the cross product is zero when the vectors are parallel.

Examples:

* Pushing a box horizontally: If you push a box horizontally at its center of mass, you'll move the box without rotating it. The force has no torque.

* Pulling a rope attached to the center of a wheel: Pulling on a rope attached to the axle of a wheel will only cause the wheel to translate (move linearly) without rotating.

Important Note: While a force acting through the center of mass doesn't create a torque, it can still cause a change in linear momentum (causing the object to accelerate).

Let me know if you'd like more examples or want to explore other aspects of forces and torques!