Applied Mechanics and Graphic Statics
The following is in unstable equilibrium

A uniform solid cone resting on a generator on a smooth horizontal plane
A uniform solid cone resting on its base on a horizontal plane
A satellite encircling the earth
A solid cube resting on one edge

ANSWER DOWNLOAD EXAMIANS APP

Applied Mechanics and Graphic Statics
A point subjected to a number of forces will be in equilibrium, if

Two resolved parts in any two directions at right angles are equal
Algebraic sum of the forces is zero
Sum of resolved parts in any two directions at right angles, are both zero
Algebraic sum of the moments of the forces about the point is zero

ANSWER DOWNLOAD EXAMIANS APP