Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

Consider the following statements regarding levers and the centre of gravity: (A) The Mechanical Advantage (M.A.) of a lever is defined as the ratio of load to effort (\( F_1/F_2 \)). (B) The Mechanical Advantage of an ideal lever is mathematically given by \( d_1/d_2 \), where \( d_1 \) is the load arm and \( d_2 \) is the effort arm. (C) The moment of a couple acting on a rigid body varies with the choice of the reference point about which moments are computed. (D) In a uniform gravitational field, the centre of gravity of a body coincides precisely with its centre of mass. Choose the correct answer from the options given below:

1. A
   (A) and (D) only
2. B
   (B) and (C) only
3. C
   (A), (C) and (D) only
4. D
   (A), (B) and (D) only