Which of the following statements are correct ?
(1) Centre of mass of a body always coincides with the centre of gravity of the body
(2) Centre of mass of a body is the point at which the total gravitational torque on the body is zero
(3) A couple on a body produces both translational and rotational motion in a body
(4) Mechanical advantage greater than one means that small effort can be used to lift a large load.

Options

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

Explanation

Centre of gravity of a body is the point at which the total gravitational torque on body is zero . Centre of mass and centre of gravity coincides only for symmetrical bodies .
Hence statements (1) and (2) are incorrect
A couple of a body produces rotational motion only.
Hence statement (3) is incorrect .
Mechanical advantage greater than one means that the system will require a force that is less than the load in order to move it .
Hence only statement (4) is correct .
None of the given option is correct .