Torque

• Torque is the twisting force that tends to cause rotation. The point where the object rotates is known as the axis of rotation. Mathematically, torque can be written as T = F * r * sin(theta), and it has units of Newton-meters.

Equilibrium

• The condition of a system when neither its state of motion nor its internal energy state tends to change with time.

Pivot Point

• Pivot point, the center point of any rotational system
• such as a lever system
• the center of percussion of a rigid body
• or pivot in ice skating or a pivot turn in dancing

Center of Gravity

• The center of gravity is the average location of the weight of an object. We can completely describe the motion of any object through space in terms of the translation of the center of gravity of the object from one place to another, and the rotation of the object about its center of gravity if it is free to rotate.

Center of Mass

• The center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may be applied to cause a linear acceleration without an angular acceleration.