Motion of Centre of Mass

A projectile of mass mis fired with an initial velocity v_(0) at an angle 0 to the horizontal. At its highest point, it explodes into two fragments of equal mass. One of the fragments falls vertically with zero initial speed. Since the only external force acting on the system is gravitational, the motion of centre of mass of the_ system (the fragments) follows the same parabolic path as the projectile would have followed if there had been no explosion. Force of explosion is internal, it cannot change the trajectory of the system.

The figure (A) and (B) shows two different arrangements of a spool being pulled with a constant force F in each case. Identify the direction of motion of centre of mass, and the direction of friction force in each case (i) The centre of mass moves along _______ x-axis in figure (A). (negative/positive) (ii) The frictional force acts along ___________ x-axis in figure (A). (negative/positive) (iii) The centre of mass moves along ____________ x-axis in figure (B). (negative/positive) (iv) The frictional force acts along _____________ x-axis in figure (B). (negative/positive)

Motion of the Centre of Mass

The position of centre of mass does not depend upon the reference frame. Centre of mass depends only upon the mass of the body.

Acceleration Of Centre Of Mass Of System

The motion of the centre of mass is the result of

A uniform straight rod is placed in vertical position on a smooth horizontal surface and released. As the rod is in motion, the centre of mass moves

The motion of the centre of mass of a system of two particles is unaffected by their internal forces.

Write an expression for the position vector of the centre of mass of n-particle system. Also write the equations of motion which govern the motion of the centre of mass

To determine the motion of the centre of mass of a system, knowledge of internal forces of the system is required. For this purpose we need not to know the external forces on the system.