orques Dynamics and Torques WCLN.ca WCLN.ca 2. The planks shown below are all of the same mass and length. They are positioned on top of a wedge so 6. Locate the center of mass, COM, on the bodies below then label all of the forces acting on the body in that they are free to rotate. Rank the images below from largest to smallest torque generated by the these two positions. Note: the force of gravity will be directed straight down and is located at the center plank's center of mass. Assume the largest is the one with the most "clockwise" torque, while the of mass. smallest is the most counter-clockwise. Fn Fn B Center of mass Center of mass Weight of board A Weight of board C D Center of mass Center of mass Weight of board V Fall 7 CM Weight of board Center of mass Weight of board I Fg IFg Largest Torque C D A E B Smallest Torque TEFT xplain how you arrived at this ranking (include references to any appropriate physics equations) HP C has the largest torque because it is the farthest P from the pivot point. B is on the pivot point Not Rotating (stable) Rotating clockwise (unstable) creating no forquoc . 3. In general, where is the center of mass located on the human body? Navel is the center of mass located on the human body. Torque, t, is a "rotational" quantity defined by a simple equation t = Fxd, where both F and d must be . Perform the following task. Stand so that you are facing a wall. Position your feet so that your toes are perpendicular to each other. Sometimes it is advantageous to find the force component that is perpendicular to d (the distance to the pivot point). Other times it is easier to leave the force and find the touching the wall where it meets the floor. While maintaining this position try to go up on your toes ("tip- toe" style). Describe what happens. Discuss rotation. perpendicular distance instead. The rotation is Clock wise because the force are On the diagram above extend each force of gravity vector so that it reaches the floor. The "pivot" will be the toes. The perpendicular distance will be the distance along the floor between the toes and the Unbalanced Frand Egore balanced but not the Fall so it is extended force of gravity. Label these distances on the diagram. creating a prepend dular angle at clock wise direction, Using these labels, explain why the person on the left rotates clockwise while the person on the right 5. Repeat the above procedure away from the wall and (hopefully) success is achieved. What changed? Pay experiences no rotation (you may have to adjust your center of mass position). attention to how your body moves. The force are balance because Fn and Eg are The person on the left solates clockwise because the cqual each other, No other forces are taking palace pivot point which is the toe is opposing the wall So it is stable Page 5 of 12 Page 4 of 12
