Moments, couples and torques

Question 1

Define a moment

Answer 1

Force x perpendicular distance from pivot

Question 2

What is the SI unit for a moment?

Answer 2

Nm

Question 3

Define a couple

Answer 3

When two parallel forces of equal magnitude act in opposite directions on the same body

Question 4

Define torque

Answer 4

Force x perpendicular distance between the forces

Question 5

How would you solve an equilibrium problem?

Answer 5

1) Choose a suitable point to act as the pivot
2) Calculate the sum of clockwise moments
3) Calculate the sum of anticlockwise moments
4) Equate the total clockwise and anticlockwise moments

Question 6

Define the principles of moments

Answer 6

For a body in equilibrium, the sum of the clockwise moments must equal the sum of the anticlockwise moments about any point