The pin attached to the bar provides an external force but not an external torque because the force acts along the line of the pin, which passes through the pivot point of the bar.
A pin attached to a bar provides an external force but not an external torque because the force acts along the line of the pin, which passes through the pivot point of the bar.
The pin provides an external force. A force is a push or pull that can cause an object to change its motion. In our case, the pin is pushing on the bar, and this force is causing the bar to move.
The force acts along the line of the pin. The line of action of a force is the imaginary line that the force acts along. In this case, the line of action of the force is the line that passes through the two ends of the pin.