Question on Torque.

is T=Fl the same as T=FD?

Probably but I do not know really what your unknowns are. L and D are the radius vector to the point of application?

Here:
https://www.youtube.com/watch?v=tQPfzScB9jg

No, T=Fl and T=FD are not the same equations for torque. Let's break down the differences and understand the concepts behind them.

1. T=Fl: This equation represents torque as the product of the force (F) and the perpendicular lever arm length (l). Torque is a rotational force that tends to cause an object to rotate around an axis. When a force is applied perpendicular to the lever arm, we can calculate the torque using this equation. The resulting torque is measured in units of Newton meters (Nm).

2. T=FD: This equation does not correctly represent torque. The correct equation for torque calculations involves the lever arm length, not the linear distance (D). The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force. While the linear distance may still be relevant in certain contexts, it does not directly relate to torque calculations.

To summarize, T=Fl is the correct equation for torque, where T represents torque, F represents the force applied, and l represents the lever arm length. Meanwhile, T=FD is not a valid equation for torque calculations as it does not accurately incorporate the lever arm length.