Torques and Moments of Force

Objectives:

• Define torque
• Be able to add multiple torques that act about a single axis of rotation
• Redefine static equilibrium
• Define center of mass, and discuss its implications regarding mechanical stability 

Most of the information from this chapter will be presented in class, without a corresponding powerpoint presentation. If you miss any class period during this chapter, you will need to see a classmate for the missed material, or you can visit me during my office hours.

Center of mass ppt

Chapter 5 Summary:

1. Torque (T), or a moment of force, can be described as the turning effect produced by a force that does not act through the axis of rotation. The mathematical description for torque is: T = F × r, where r indicates the perpendicular distance between the force and the axis of rotation.
2. If you are considering torques about the same axis of rotation, you can algebraically add them; counterclockwise torque is represented as positive torque and clockwise torque is represented as negative torque.
3. The sum of the torques about a single axis is called net torque.

4. In order for an object to be in static equilibrium the following equations must be satisfied:

    

   ΣF = 0;               ΣT = 0;

    

5. The center of mass is a theoretical location at which all of the mass of an object is centered.

6. Stability is the ability of an object to return to equilibrium, after being perturbed. Stability is affected by three primary mechanical factors:
   1. The nature of the base of support;
   2. The height of the center of gravity;
   3. The weight of the considered object.

Torque Homework