6.6 Equilibrium rules

Question 1

Define free body force diagram

Answer 1

a diagram of an object showing only the forces acting on the object

Question 2

How can a point object being acted on by 3 forces be in equilibrium?

Answer 2

The 3 forces must give an overall resultant force of 0.

Question 3

What 2 conditions are required for equilibrium of a body?

Answer 3

1. the resultant force must be 0. If there are only 3 forces, they must form a closed triangle
2. the principle of moments must apply (moments of forces about the same point must balance out.)