Which of following statements are correct ? ltbgt (a) Centre of mass of a body always coincides with the centre of gravity of the body
(b) Central of mass of a body is the point at which the total garvitational torque on the body is zero
(c ) Couple on a body produces both trasnlational and rotation motion in a body
(d) Mechinical advantage greater than one means that small efforts can be used to lift a large load

Options

A. (a) and (b)
B. (b) and (c )
C. (c ) and (d)
D. (b) and (d)

Explanation

(a) Centre of mass of centre of gravity will coincide if accerlation due to gravity is same.
(c ) Couple produces only rotaional motion
Mechanical advantage `= ("load")/("effort") gt 1`
i.e., load gt effort