Question

What does the moment of force measure?
(A) The tendency of rotation of the body along any axis
(B) The moment of inertia of the body about any axis
(C) The couple moment produced by the single force acting on the body
(D) The total work done on the body by the force

Answer 1

Hint
Moment of force is responsible for making an object rotate about an axis. Depending on the position of the axis and the distance of the force acting, the value of the moment may vary.

Complete step by step answer
The moment of force is also better known as the torque or simply the moment. It determines the tendency of a force to rotate the body of application about a specific point or axis of rotation. Since force is a vector quantity and so is the radial distance between the point of application of the force and the pivot, the moment of force is calculated by taking the cross product of the two. Its direction is determined by using the right hand thumb rule. Now let us evaluate all the options to see which one is the correct.
As the term inertia implies resistance to movement, moment of inertia is the resistance to angular movement. It is helpful in determining the angular momentum of a body.
Couple moment by definition is the moment produced by two forces of equal magnitude but opposite direction. Hence, it cannot be generated by a single force.
Hence, the correct answer is option (A) i.e. the tendency of rotation of the body along any axis.

Note
A simple example of moment of force or torque is a hinged door. To open the door we push or pull the farthest end from the hinge point. This causes a rotational motion of the door and it opens. If we push very close to the hinge point, it would require us to use a lot of force and still the door might not open.