Center of Mass- physics

C of M definition

the mass-weighted avg position of all the mass of the object

Object with constant density and symmetrical shape

the center of mass is directly in center of object

Parabola (parabolic path)

shape of path created by object moving in projectile motion

As long as object is in a constant gravitaitonal field

the C of M and center of gravity of an object are in same location

True for all objects in projectile motion

follows parabolic path, can treat each obj as if Fg acts on the object’s center of mass

Systems (three balls moving relative toward each other)

still have a center of mass which moves in a parabolic projectile motion

thin rod (two ice cubes)

typical C of M of two objects connected by a thin rod, applied force on left or right rotates system

If you apply an object at, or directly toward its center of mass

the force applied will not cause the object to rotationally accelerate- force will only cause a linear acceleration of object

Cannot assume all C of M of objects are located

near the geometric centers of the objects

Hanging Wood Ex

Fg pulls on C of M of wood to bring C of M to lowest point

symbol (black and white shaded in 4)

typically used to indicate the C of M of an object

Egg example

as egg is tipped over, C of M goes up, Fg pulls down on C of M when if let go of egg, the C of M is pulled downward and C of M goes to lowest position