tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction

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

remain horizontal

slant up towards direction of pull

slant down towards direction of pull

unpredictable

r/2

r/A

r/%

0.134 r

equal to the moment of the couple

constant

both of above are correct

both of above are wrong

balance each other

cannot balance each other

produce moment of a couple

are equivalent