Strength of Materials
A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if

the floor and wall both are rough sur-faces
the floor is rough, the wall is smooth
the floor and wall both are smooth surfaces
the floor is smooth, the wall is rough

ANSWER DOWNLOAD EXAMIANS APP

Strength of Materials
According to principle of moments

if a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero
if a system of coplanar forces is in equilibrium, then their algebraic sum is zero
positive and negative couples can be balanced
the algebraic sum of the moments of any two forces about any point is equal to moment of theiwesultant about the same point

ANSWER DOWNLOAD EXAMIANS APP

Strength of Materials
Kinetic friction is the

Ratio of limiting friction and normal reaction
The friction force acting when the body is just about to move
The friction force acting when the body is in motion
Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction

ANSWER DOWNLOAD EXAMIANS APP