Which of the following statements are correct?
- Centre of mass of a body always coincides with the centre of gravity of the body.
- Centre of mass of a body is the point at which the total gravitational torque on the body is zero.
- A couple on a body produce both translational and rotational motion in a body.
- Mechanical advantage greater than one means that small effort can be used to lift a large load.
Answer & explanation
Correct answer: option 2
Centre of mass may or may not coincide with centre of gravity.
CoM is a point where whole mass is concentrated and hence, torque is zero.
Mechanical advantage : M = \(\frac{\text{output force}}{\text{input force}}\)
If M > 1, \(\Rightarrow \text{output} > \text{input}\)
Thus, less effort is required to lift large road.