Rotational Motion: Why Does External Torque Affect Axis?

[harshu]

Why does a body always rotate about an axis through the center of mass only when an external torque is applied to it?

 

[Shooting Star]

That is not true. Try to reformulate your question.

 

[charng]

External torque affects the axis of rotational motion because it is the force that causes rotation around a specific point or axis. When a force is applied to an object, it creates a torque, which is a measure of the force's ability to cause rotation. This torque is then transmitted to the object's center of mass, causing it to rotate around that point.

In order for a body to rotate about a specific axis, there must be a net torque acting on it. This net torque is the sum of all the individual torques acting on the object. When an external torque is applied, it creates an imbalance of forces that causes the object to rotate around its center of mass.

Additionally, the center of mass is the point at which an object's mass is evenly distributed, and it is the point around which the object's rotational motion occurs. This is why a body will always rotate about its center of mass when an external torque is applied, as the torque is transmitted to this point and causes the object to rotate around it.

In summary, external torque affects the axis of rotational motion because it is the force that causes an object to rotate around its center of mass. Without an external torque, there would be no net torque and the object would not rotate. Therefore, external torque is essential for causing rotational motion and determining the axis of rotation for a body.