The discussion focuses on calculating the length of the moment arm and the torque about a point due to a force vector, denoted as F→F_vec. The correct expression for the moment arm is r sin Θ, where the sign of the torque τ is determined by the direction of rotation: counterclockwise (ccw) is positive and clockwise (cw) is negative. The moment arm is defined as the perpendicular distance from the line of action of the force to the point of rotation, which is crucial for accurate torque calculations. The cross product rule is also mentioned as an alternative method for calculating torque.
PREREQUISITESStudents studying physics, particularly those focusing on mechanics, engineers working with rotational systems, and educators teaching torque concepts.
always use the magnitude ( positive number) of the force and position vectors and moment arm when calculating torques. The sign of the torque is then determined by clockwise or counterclockwise torque , ccw is plus in this example, cw is minus, simply by convention.negation said:
PhanthomJay said:
There are several ways to calculate torque about a point. One such way is to use torque = magnitude of force times the perpendicular distance from the line of action of the force to point, where the perpendicular distance is called the 'moment arm'. Another is to use the cross product rule. Sign of torque is plus if ccw, minus if cw, using the convention that ccw torques are positive.negation said:
PhanthomJay said:
No, the moment arm is the perpendicular distance from the line of action of the force vector to the point, which woukld be rm on your sketch.negation said: