Question

1)define pitch of a screw
2)define equilibrant.
and
3)define moment of force

Answer 1

The pitch of a screw is the distance between threads. With each complete rotation of the screw, it goes in or out a distance equal to its pitch. 
Equilibrant force is a force which brings equilibrium state. It is considered to be the equal and opposite of the resultant force. Equilibrant force is the force, which keeps any object motionless and acts on virtually every object in the world that is not moving.
The turning effect of a force is known as the moment. It is the product of the force multiplied by the perpendicular distance from the line of action of theforce to the pivot or point where the object will turn.