Category: Strength of Materials

Kinetic friction is the________________?

A. tangent of angle between normal reac-tion and the resultant of normal reac-tion and the limiting friction
B. ratio of limiting friction and normal reaction
C. the friction force acting when the body is just about to move
D. the friction force acting when the body is in motion
E. dynamic friction

Coefficient of friction is the__________________?

A. angle between normal reaction and the resultant of normal reaction and the limiting friction
B. ratio of limiting friction and normal reaction
C. the friction force acting when the body is just about to move
D. the friction force acting when the body is in motion
E. tangent of angle of repose

According to principle of moments_________________?

A. if a system of coplanar forces is in equilibrium, then their algebraic sum is zero
B. if a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero
C. the algebraic sum of the moments of any two forces about any point is equal to moment of theiwesultant about the same point
D. positive and negative couples can be balanced
E. none of the above

According to Lami’s theorem________________?

A. three forces acting at a point will be in equilibrium
B. three forces acting at a point can be represented by a triangle, each side being proportional to force
C. if three forces acting upon a particle are represented in magnitude and
direction by the sides of a triangle, taken in order, they will be in equilibrium
D. if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two
E. none of the above