Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

Consider the following statements regarding the Centre of Gravity (CG) and Centre of Mass (CM) of an extended body: (A) The centre of gravity is defined as the point where the total gravitational torque on the body is zero. (B) The centre of gravity of a body always coincides with its centre of mass, even in a non-uniform gravitational field. (C) For an irregular body suspended by a string, the vertical line passing through the point of suspension passes through the centre of gravity. (D) When a cardboard balances horizontally on the tip of a pencil, the normal reaction of the tip balances the total weight and exerts zero net torque about the CG. How many of the above statements are correct?

1. Only one
2. Only two
3. Only three
4. All four